Objective: To investigate the value of preoperative multi slice spiral CT (MSCT) in the diagnosis of tumor deposition (TD) adjacent to colorectal cancer. Methods: The preoperative whole abdominal MSCT data of 50 patients with colorectal cancer confirmed by surgery and pathology were retrospectively analyzed. The imaging characteristics of TD were observed, and the parameters of TD and metastatic lymph nodes in the same region were measured. The CT imaging characteristics and related measurement parameters of TD and metastatic lymph nodes were compared and analyzed. Results: Among the 50 patients with colorectal cancer, 78 TD lesions and 35 metastatic lymph nodes were confirmed. TD lesions were (2.63±0.70) cm away from the primary tumor, mainly located in the fat space around the colorectal, accounting for 91.03%; most of the lesions were irregular in shape, showing lobulated sign or edge burr sign, accounting for 82.05%; 67 TD lesions had uniform density on plain scan, obvious enhancement on dual phase enhanced scan, which was close to the enhancement degree of the primary tumor; 11 TD lesions had liquefaction necrosis. The metastatic lymph node lesions were regular in shape, with smooth edge, and mostly round or oval, accounting for 88.57%. Comparison of MSCT related parameters: the long diameter, short diameter and maximum diameter of TD lesions were longer than those of metastatic lymph nodes, and the CT value of plain scan, arterial phase enhanced CT value and venous phase enhanced CT value were higher than those of metastatic lymph nodes (P<0.05); there was no statistically significant difference in CT value between TD lesions and primary tumor lesions (P>0.05). Conclusion: Preoperative MSCT examination can show a variety of imaging features of TD adjacent to colorectal cancer, which is helpful for clinical diagnosis and differential diagnosis of metastatic lymph nodes.