Low-grade rectal cancer refers to rectal cancer with the lower margin of the tumor less than 7 cm from the anal verge or located in the lower 1/3 of the rectum. Pathological studies have confirmed that the infiltration of rectal cancer into the distal intestinal wall is limited, with less than 3% exceeding 2 cm. Therefore, resection of the distal segment of rectal cancer greater than 2 cm is sufficient, thus expanding the indications for low anterior resection of rectal cancer and providing a theoretical basis for anus-preserving surgery for low rectal cancer. At the same time, a large number of clinical practice and pelvic floor trial studies have shown that as long as the anal canal, anal sphincter and anal levator muscle are preserved intact, the anus can be preserved and normal defecation function can be maintained. Pathological research has led to a deeper understanding of the biological behavior of rectal cancer, and specialization has made colorectal surgeons more skilled in anus preservation techniques. The emergence of various anastomoses, especially the application and improvement of double anastomoses, has led more and more surgeons to challenge the previously impossible technique of ultra-low anastomosis and to adapt to the increasing demand for anus preservation in rectal cancer patients. With the widespread use of dual anastomosis technology, it has been found that for certain patients with a narrow pelvis and obesity, the previous linear closure has many shortcomings, depriving some patients of the opportunity to preserve anus. The curved cutting anastomosis has a unique curved head design that conforms to the pelvic structure of the human body and can easily reach deeper into the pelvic floor. It completes cutting and suturing simultaneously, further reducing the chance of contamination and avoiding the difficulty of rectal dissection in a very narrow space with linear closures and the possibility of side injuries caused by this; the curved cutting anastomosis simplifies the operation steps of distal rectal resection and shortens the operation time. shortens the operative time and makes the double anastomosis technique easier to perform. In the literature, the incidence of postoperative anastomotic fistula is usually between 2.5 and 5.0% when using the linear anastomosis technique. The incidence of postoperative anastomotic fistula was 4.3% in 46 cases of low rectal cancer with the use of the curved cutting anastomosis clutch, and no anastomotic bleeding or stricture occurred, indicating that the use of the curved cutting anastomosis clutch facilitated the successful completion of anterior resection of ultra-low rectal cancer without increasing the incidence of anastomotic complications. However, more data are needed to confirm the advantages of the curved cutting anastomosis compared with the linear anastomosis in reducing the incidence of anastomotic fistula. Complications of low anastomosis preservation for rectal cancer using the curved cutting anastomosis clutch are similar to those of the linear suture device and include anastomotic leak, anastomotic bleeding, anastomotic stricture, positive incisional margin and rectovaginal fistula, postoperative urinary retention, and sexual dysfunction. There was no anastomotic bleeding, anastomotic stenosis and rectovaginal fistula in the whole group, while there were 2 cases of anastomotic fistula. Combining the literature and summarizing our group’s experience, the main reasons for the occurrence of anastomotic fistula with the application of the arc-cut anastomosis are local factors such as deep anastomotic location, difficult operation, poor local blood supply or high tension, intraoperative contamination, poor postoperative drainage, and systemic factors such as poor general condition, obesity, narrow pelvis, preoperative antitumor treatment, and combined diabetes mellitus. In order to prevent the occurrence of anastomotic fistula, the following aspects of treatment should be emphasized when using the curved cutting suture to perform low anus-preserving surgery for rectal cancer: (1) Fine surgical operation and skillful use of anastomotic instruments. (2) Ensure that the anastomosis is tension-free, and moderately resect the proximal colon under the premise of radical treatment. If tension is suspected in the anastomosis, the proximal colon should be fully freed or the splenic flexure of the colon should be loosened. (3) Good blood supply to the anastomosis. The freeing range of the intestinal tract at the distal and proximal ends should not be too large, the fatty drape of the intestinal wall should be moderately removed, the vascular pulsation at the edge of the proximal colon should be strong, and the intestinal tube should be well colored. (4) Selection of anastomotic site: the anastomosis should be made at the midpoint of the closed rectal margin on the dorsal side, and the lower rectal resection of the intestinal wall should contain part of the closed rectal margin. Because, usually, the free range of the dorsal side of the rectum is larger than the ventral side, the blood supply is relatively poor, and the anastomosis here can reduce the dorsal bloodless area; at the same time, if a bridle is formed between the cut edge of the tubular anastomosis and the closed edge of the rectum, it is easy to cause ischemic necrosis of the intestinal wall of the bridle and fistula occurs. (5) After the anastomosis is completed, the upper and lower resection rings should be checked immediately for completeness. If there is a defect, the suture can be reinforced at the corresponding area. At the same time, an anal finger examination is performed after the anastomosis to check whether the anastomotic staple is a regular circle, and female patients are routinely inspected on the posterior vaginal wall to ensure that there is no anastomotic injury. In conclusion, the curved cutting anastomosis as an improvement of the double anastomosis technique with a unique curved design to access a lower position in the pelvis, its application in low anterior rectal resection is safe and effective, especially for patients with low tumor location and difficult operation to provide instrumentation support.