The incidence of rectal carcinoid tumor is low, and the tumor is generally small (most of them are < 1cm in diameter), which is often clinically asymptomatic, and hard nodes of rectal wall can often be found on rectal finger examination, which are active and without pressure pain. Rectal carcinoid tumor is difficult to diagnose clinically, and only biopsy can confirm the diagnosis. Since the tumor is often located under the mucosa, it is not easy to get the tumor tissue by biting biopsy, so it often needs to be removed for biopsy. Histopathological examination alone cannot determine the benignity and malignancy of rectal carcinoid tumor, so pathologists and surgeons can work together to determine its malignancy. The determination of benignity and malignancy of rectal carcinoid tumor can be based on four aspects: tumor size, whether it infiltrates the muscular layer, whether it is solitary or multiple, and whether it has clinical symptoms. Because of the "benign" appearance of rectal carcinoid tumor and the small size of the tumor, people mistakenly think that it can be cured by simple removal, however, clinically, there are many rectal carcinoid tumor patients who recurred, spread and eventually died due to improper treatment. However, many patients with rectal carcinoid tumors have recurrence and spread due to improper treatment, and eventually died. The reasonable selection of surgical method for rectal carcinoid tumors should take into account the specific location and size of the carcinoid tumor as well as the pathological results of preoperative biopsy. Generally speaking, when a rectal wall nodule is found and the biopsy pathology suggests (or is suspected of) rectal carcinoid tumor, if the tumor diameter is < 1 cm and there is no clinical symptom, the tumor can be excised completely according to the specific location of the tumor and combined with the operator's surgical experience, and the tumor can be sent to pathological examination immediately after surgery to confirm that there is no residue on the cut edge; if the tumor diameter is > 2 cm, the biopsy pathology or preoperative EUS (or ultrasound colonoscopy) suggests If tumor diameter is > 2 cm, biopsy pathology or preoperative EUS (or ultrasound enteroscopy) indicates muscle layer invasion or obvious ulcer, various radical resections (such as Dixon, Parks or Miles) should be chosen according to the specific site of tumor; if tumor diameter is 1~2 cm, local enlargement resection should be performed and pathological examination should be done after surgery to clarify whether there is muscle layer infiltration or not, if there is muscle layer infiltration, radical resection should be performed again in principle. In principle, radical resection should be performed again if there is muscle layer infiltration. If the tumor recurs after local resection or local enlargement resection, radical resection should be performed if there is muscle layer infiltration or multiple rectal carcinoid tumors. Of course, on the basis of complete and total resection, we should prevent over-treatment by expanding the scope of surgery, because most rectal carcinoid tumors are in the middle and lower rectum, and it is difficult to preserve the anal function if they are not treated properly. Before deciding to perform Miles surgery, there should be sufficient evidence to show that the tumor is malignant, accompanied by muscle invasion and the location of the tumor is too low to preserve the anus. Among the various local resections, the traditional transanal resection is most commonly used by surgeons to treat rectal carcinoid tumors. Mason’s procedure and TEM provide ideal options for patients with rectal carcinoid tumors suitable for local resection: (1) Mason’s procedure uses a trans-sacral transanal sphincter pathway for good field exposure and easy to perform partial rectal resection at 1 cm from the tumor margin, or a partial rectal resection at 1 cm from the tumor margin. It is easy to perform partial or segmental resection of the rectum 1 cm from the tumor margin. Our clinical practice has demonstrated that this procedure has the advantages of less trauma, direct access and superficial field than the transabdominal approach in the treatment of middle and lower rectal diseases (including rectal carcinoid tumors), which can make some rectal procedures that are difficult to perform via the abdomen simple and safe. Likewise, it has a larger operating space than the transanal route and the trans-sacral route (Kraske’s procedure), thus making the operation more precise and avoiding tumor margin residue or under-resection. (2) TEM is a relatively new minimally invasive surgical technique for rectal tumor treatment, which can complete a series of operations such as resection, hemostasis and suturing through endoscopy, and combines the characteristics of endoscopy, laparoscopy and microsurgery. It has obvious advantages compared with traditional local resection.