Objective To explore the diagnostic value of spiral CT three phase enhanced scan in the diagnosis and staging of colorectal cancer. Methods A total of 58 patients with colorectal cancer in our hospital from January 2015-2016 year in December were collected from 58 patients of the data, and the pathological examination results as the standard, analyze the accurate diagnosis rate of CT phase three enhanced scan in clinical staging (T), lymph node metastasis (N) and distant metastasis (M) of patients with colon cancer. Results CT three phase enhanced scan in patients with colon cancer T staging, the accuracy of T1-2 staging was 94.11% (16/17) 3, T staging accuracy rate was 85.71% (18/21), the accuracy of T4 staging was 95% (19/20).The diagnostic accuracy of CT three phase enhanced scan for N0 staging was 93.33% (28/30), the accuracy rate of N1 staging was 87.50% (14/16), and the accuracy rate of N2 staging was 91.66% (11/12). The accuracy of CT three phase enhanced scan in diagnosing M staging of colon cancer was 94.82% (55/58). Compared with pathological staging results, there was no significant difference in the diagnostic accuracy of T, N and M staging in patients with colon cancer by CT three phase enhancement scanning (P>0.05). Conclusion spiral CT three phase enhanced scan can accurately diagnose and staging colon cancer, and provide reliable imaging data for clinical treatment.