Abstract： Objective To explore the associations of triple-phase enhancement multi-slice CT scan with histological differentiation and lymphovascular invasion in advanced gastric cancer. Methods Patients with gastric cancer undergoing surgical resection between January 2006 and December 2009 were included, all of whom underwent routine and two-phase contrast enhancement multi-slice CT examinations of the upper abdomen before surgery. Patients with incomplete data were excluded. Postoperative specimens were used for evaluation of histological differentiation, microscopic lymphovascular invasion, and CD34 and D2-40 expression. Associations between contrast enhancement ratio(CER) of triple-phase multi-slice CT scan and differentiation as well as lymphovascular invasion were analyzed. Results A total of 64 patients were included. There were significant associations between CER and tumor differentiation(P＜0.05). Compared to those without microvascular invasion, CER of the arterial phase in gastric cancer with microvascular invasion was significantly higher(0.61±0.28 vs. 0.46±0.14, P＜0.05), and that of the arterial-parenchymal phase was significantly lower(1.81±0.39 vs. 2.28±0.80, P＜0.05). However, gastric cancers with lymphatic invasion were associated with significantly higher CER of the parenchymal phase than their counterparts(1.25±0.57 vs. 1.00±0.35,P＜0.05). Conclusion CER of triple-phase multi-slice CT scan can reveal the differentiation of gastric cancer and is associated with microvascular and lymphatic invasion.