Objective Explore the impact of a multimodal pre-rehabilitation intervention based on a tertiary diagnostic model of malnutrition on nutritional status gastrointestinal function and prognosis recovery in patients with colorectal cancer. Method According to the inclusion and exclusion criteria 224 colorectal cancer patients collected from the Second Affiliated Hospital of Xi'an Medical University between March 2021 and March 2024 were selected as the subjects of this study. Four of them were lost to follow-up. The final prognosis of 220 colorectal cancer patients. Follow the principle of sealed envelope method conduct random sampling for grouping it was divided into 2 groups. In the control group 110 patients were treated with a conventional rehabilitation intervention the observation group of 110 patients underwent a multimodal pre-rehabilitation intervention based on a tertiary diagnostic model of malnutrition. Two groups at 30 d after the intervention comparing the serum nutritional index physical and physical examination gastrointestinal barrier function and quality of life scale QLQ - C30 scores at the same time the incidence of postoperative complications during hospitalization was counted. Result After 30 d of corresponding intervention serum nutritional index physical and physical examination results gastrointestinal barrier function and QLQ-C30 scores improved compared with the same intervention P < 0. 05 . Comparing the two groups after intervention the improvement of Hb TP ALB DAO ET and D-LAC at 30 d after intervention was better than the control group P <0. 05 BMI TSF AMC and QLQ-C30 score scores were higher than the control group P <0. 05 and the postoperative complication rate 2. 73% vs 13. 64% was also lower than that of the control group P <0. 05 . Conclusion Multimodal pre-rehabilitation based on the tertiary diagnostic model of malnutrition can improve the postoperative intestinal barrier function and nutritional status of colorectal cancer patients reduce related complications and improve the quality of life which has significant significance for postoperative recovery.