Objective To study the correlation between the CT expression and the degree of tissue differentiation in patients with advanced gastric cancer. Methods 82 cases with advanced gastric cancer were selected from January, 2012 to June, 2014 who were admitted in our hospital, all the patients revealed advanced gastric cancer by biopsy, CT was performed on these patients, to analyze the correlation between the CT expression and tissue differentiation degree. Results 82 cases of advanced gastric cancer patients which are 9 (10.98%)of polyp type, 10 (12.20%) of ulcerative type, 63 (76.83%) of infiltration type, the overall accuracy of 98.78% (X2 =13.12, P=0.002), with statistical significance. CT revealed 82 patients with advanced gastric cancer in high differentiation of 32 (39.02%), 26 (31.71%) in medial differentiation, 24 (29.27%) of infiltration type, the overall accuracy of 84.15% (X2 =11.29, P=0.003), with statistical significance. Pearson analysis showed that the thickness of disease progression in patients with gastric cancer (X2 =12.35, P=0.003), lymph node metastasis (X2 =9.64, P=0.004), the difference value of enhancement(X2 =13.26, P=0.002) related to the degree of differentiation (rs =0.46, P=0.003), with statistical significance. Conclusion CT expression is closely related to tissue differentiation in patients with advanced gastric cancer. Multi slice spiral CT can accurately evaluate its degree of histological differentiation.