Objective: To analyze the pharmacological treatment process of postoperative complications of incisional infection and pulmonary infection in a patient with rectal cancer undergoing radical resection, and provide reference for the rational use of clinical drugs. Methods: The clinical pharmacist, by analyzing the patient's current condition and reviewing relevant literature, assisted the clinician in optimizing and adjusting the anti-infection treatment regimens and other adjuvant treatment regimens for the postoperative complications of incisional infection and pulmonary infection in the patient with rectal cancer undergoing radical resection. Results: By analyzing the patient's microbiological culture and drug susceptibility test results, as well as the antibacterial action characteristics of tigecycline and ceftizoxime, the clinical pharmacist advised the clinician to adjust the anti-infection treatment regimens in a timely manner to cover Pseudomonas aeruginosa, and to optimize the nutrition support plan and medication courses of proton pump inhibitors, resulting in rapid improvement of the patient's condition. Conclusion: For postoperative complications of infectious diseases in such cancer patients, the clinical pharmacist should pay particular attention to the results of microbiological culture and drug susceptibility tests, comprehensively consider the action characteristics of antibacterial drugs, and assist the clinician in formulating scientific and reasonable anti-infection treatment regimens, as well as optimize adjuvant supportive treatment regimens to ensure the success of patient treatment.