Rectal cancer stage 3a, only a small portion of which can be cured, and most of which cannot be cured. According to TNM staging of colorectal cancer, stage 3a rectal cancer includes T1N1M0, T2N1M0, T1N2aM0, T1 refers to tumor invasion of submucosa, T2 refers to tumor invasion of intrinsic muscularis propria, N1 refers to 1~3 regional lymph node metastasis; N2a refers to 4~6 regional lymph node positivity. m0 refers to the absence of distant metastasis. According to the recommendations of rectal cancer treatment guidelines, stage 3a rectal cancer requires preoperative neoadjuvant chemotherapy and postoperative adjuvant chemotherapy, and simple surgical treatment has less chance of cure. As regional lymph node metastasis has already occurred in stage 3a, only a small portion can be completely cured. To treat stage 3a rectal cancer, comprehensive assessment is needed to choose appropriate treatment plan, and it is recommended to seek medical treatment in time, and under the guidance of professional doctors, reasonable and standardized treatment can improve the curative effect.