Objective: To investigate the relevant clinicopathologic factors for perineual invasion (PNI) in gastric cancer patients. Methods: The clinical and pathological data of 509 gastric cancer patients treated in the Affiliated Hospital of Jiangsu University from June 2014 to June 2017 were collected. The relations of PNI with clinicopathologic factors were analyzed. Results: Of the 509 gastric cancer patients, 250 cases were PNI positive and 259 cases were PNI negative. Univariate analysis showed that PNI in gastric cancer was significantly associated with the tumor infiltration depth, degree of tissue differentiation, lymph node metastasis and TNM stage (all P<0.001), but irrelevant to age and gender (both P>0.05). The χ2 tests for trend reported that PNI had a maximum correlation with tumor infiltration depth (r=0.623, P<0.001). The binomial Logistic regression analysis showed that tumor infiltration depth was an independent risk factor for PNI (OR=6.285, 95% CI=4.009–9.854, P<0.001). Conclusion: PNI in gastric cancer patients is associated with the degree of tissue differentiation, tumor infiltration depth, lymph node metastasis and TNM stage, in which the tumor infiltration depth is probably the most important factor.