Objective To evaluate the value of multi-detector row spiral CT multi-planar reconstruction (MPR) technique in diagnosing the gastric cancer invasion serosal. Methods 36 cases confirmed by surgery pathology of gastric cancer with completed scanning data of preoperative low water filling method to triplephase enhancedMSCT. Then respectively, the images were analyzed form the cross-sectional images compared with MPR images by two radiologists who were with high qualification, and determined the diagnosis of gastric cancer invasion on the gastric serosa compared with surgical pathology finally. Statistical analysis was performed using SPSS 13.0 software. Using Chi-square test performed comparison of the cross sectional images and MPR images, and P <0.05 is statistically significant. Results The accuracy, sensitivity and specificity of cross sectional image in diagnosis of serosal gastric cancer invasion were 66.67%, 63.64%and 71.43%, compared with MPR were 86.11%, 86.36%and 85.71%. MPR was significantly higher in diagnosis of gastric cancer whether infringing the serosal or not, and the difference was statistically significant (p < 0.05). Conclusion Multi-detector row spiral CT multi-planar reconstruction (MPR) technique can increase greatly the detection rate of gastric cancer surrounding invasion, improve theaccuracy of the preoperative T staging of gastriccancer.