• With my consent and signed informed consent, willing and able to comply with the planned visits, research treatment, laboratory tests, and other test procedures.

• Age 18-75. Patients with a pathologically or cytologically confirmed adenocarcinoma of the rectum, all other histological types excluded.

• The distance between the lower margin of the rectal tumor lesion and the anal margin \<12 cm.

• The physical status score (ECOG) of the Eastern Cooperative Oncology Group was 0-1 (see Appendix 1).

• T3-4/N+ was evaluated by pelvic enhanced MRI. Had not received systemic anti-tumor therapy for colon cancer, including cytotoxic drugs, immune checkpoint inhibitor therapy, molecular targeted therapy, endocrine therapy, etc.

• Appropriate organ function based on the following laboratory test values obtained during the screening period: white blood cell count ≥3 × 10\^9/L, neutrophil count ≥1.5 × 10\^9/L, platelet count ≥75 × 10\^9/L, serum total bilirubin ≤1.5 × upper limit of normal (UNL), AST (SGOT) or ALT (SGPT) ≤2.5 × UNL, serum creatinine ≤1.5 × UNL.

• Female subjects of reproductive age must undergo a negative serum pregnancy test within 3 days prior to the start of the study drug and be willing to use a medically approved highly effective contraceptive method (such as an IUD, contraceptive pill, or condom) during the study period and within 3 months after the last study drug administration; male subjects whose partners are women of reproductive age should be surgically sterilized or agree to use effective contraception during the study period and for 3 months after the last study dosing.

• Willing and able to comply with research procedures and visit plans.