Objective To investigate the relationship between nutritional status and functional limitation under the endoscopic care pathway and to clarify the impact of hemoglobin levels and protein intake on functional impairment in elderly colorectal cancer patients providing evidence for peri - endoscopic functional maintenance. Method Data from the NHANES 2005 - 2018 were analyzed. Patients aged ≥60 years with colorectal cancer were included. Hemoglobin levels protein intake and functional limitation were assessed. Restricted cubic spline RCS was used to explore non -linear associations. Logistic and linear regression analyses evaluated the relationship between nutritional exposures and functional limitation risk and severity. Subgroup analyses explored the effects of gender BMI and diabetes. Result A total of 319 patients were included with a functional limitation prevalence of 60. 8%. Functional limitation risk increased significantly when hemoglobin was below 130 g / L or protein intake was below 60 g / d P < 0. 001 . Each 10 g / L increase in hemoglobin reduced functional limitation risk by 34% each 1 g increase in protein intake reduced risk by 2%. Patients with anemia and low protein intake had the highest risk OR = 19. 68 95% CI = 4. 20-92. 17 P < 0. 001 . Subgroup analyses showed stronger associations in males lower BMI and non-diabetic patients. Hemoglobin and protein intake were negatively associated with functional limitation scores. Conclusion Hemoglobin levels and protein intake are protective factors against functional limitation in elderly colorectal cancer patients undergoing endoscopic care. Optimizing nutritional status should be integrated into the endoscopic nursing pathway to enhance perioperative functional reserves.