Objective To investigate the changes of gastrointestinal hormone and body composition in patients with gastric cancer after gastrectomy. Methods Thirty-eight patients with gastric cancer were divided into three groups: distal gastrectomy group, proximal gastrectomy group and total gastrectomy group and 9 volunteers as control group. The nutrition status and gastrointestinal function were evaluated by four times. The time of postoperative first anal exsufflation and defacation, hospital stay and complications were recorded, and the pre-meal and the post-meal level of gastrointestinal hormones 1 month after operation were detected. Results Compared with control group, the basic levels of somatostatin (SS), cholecystokinin (CCK) and motilin (MTL) of distal gastrectomy group, proximal gastrectomy group and total gastrectomy group significantly increased (Plt;0.01). The post-meal level of gastrointestinal hormones significantly increased as compared with the pre-meal level in each group (Plt;0.01). The CCK in proximal gastrectomy group was lower than that of distal gastrectomy group and total gastrectomy group (Plt;0.01). The postoperative body weight and body composition in each group decreased. One month after operation, patients of total gastrectomy group got the lowest body weight (Plt;0.01). The decreasing level of fat free mass (FFM) was listed by total gastrectomy group, proximal gastrectomy group and distal gastrectomy group. The edema index had significant difference in distal gastrectomy group, proximal gastrectomy group and total gastrectomy group (Plt;0.01), and total gastrectomy group was the most obvious. The postoperative passing flatus and defecation time and average hospital stay in total gastrectomy group were significantly prolonged (Plt;0.05). The gastrointestinal symptoms score among three groups was significantly different (Plt;0.05). Conclusion There are different changes of gastrointestinal hormone and body composition in patients with gastric cancer after different gastrectomy, the basic levels of SS, CCK and MTL of distal gastrectomy group, proximal gastrectomy group and total gastrectomy group are higher than those of control group. The CCK of proximal gastrectomy group is lower than that of distal gastrectomy group and total gastrectomy group. Patients received total gastrectomy lose much body weight and FFM and get higher edema index.