Objective To explore the application effect of Andrias davidianus peptide composite powder for the patients with gastrointestinal cancer, and provide reference for making the treatment program of nutritional support. Methods A total of 46 patients with gastrointestinal cancer treated in the Second Hospital of Dalian Medical University from April to September 2022 were divided into the two groups according to the random number table method, 23 cases for each group. Patients in the control group were given routine nutritional support treatment, and patients in the test group were treated with Andrias davidianus peptide composite powder on the basis of the control group, both groups were treated for 21 days. The levels of the nutritional status indexes [serum albumin (ALB), total protein (TP), prealbumin (PA)], liver function indexes [serum gamma-glutamyltransferase (GGT), aspartate aminotransferase (AST), alanine aminotransferase (ALT)] and renal function indexes [urea (Urea), creatinine (Cr), uric acid (UA)] of patients in the two groups before and after treatment were compared. Results Compared with before treatment, the levels of serum ALB and TP of patients in the control group and the levels of serum PA of patients in the two groups significantly decreased after treatment, but the levels of serum ALB and TP of patients in the test group after treatment were significantly higher than those in the control group (all P<0.05); the comparisons of the levels of serum ALB, TP of patients in the test groupbefore and after treatment, and the levels of PA of patients in the two groups after treatment, the difference was not statistically significant (all P>0.05); the intra-group and the inter-group comparision of the levels of serum GGT, AST, ALT, Urea, Cr and UA of patients, the difference was not statistically significant (all P>0.05); there was no adverse reactions such as diarrhea, abdominal distension and allergy were found among the patients in the test group and the control group during the treatment. Conclusion Patients with gastrointestinal cancer oral supplement Andrias davidianus for enteral nutrition support after operation can effectively improve the nutritional status of patients, and has little influence on liver function and renal function, and which has good security and is conducive to the patients’ postoperative rehabilitation.