Objective To compare the effect of laparoscopic surgery and open surgery on the blood coagulation state in patients with gastric cancer, and to provide evidence for the prevention measurement of thrombosis in perioperative period. Methods One hundred patients with gastric cancer who received treatment in our hospital from Feb. 2014 to Aug. 2014, were randomly divided into laparoscopy group and laparotomy group, 50 patients in each group. The patients in laparotomy group were treated by traditionally open surgery, while patients in the laparoscopy group accepted laparoscopic surgery. The clinically therapeutic effect of 2 groups was compared. Results ① Operative indexes. The operation time, blood loss, anal exhaust time, hospital stay, and morbidity of laparoscopy group were all lower than those of laparotomy group (P<0.05). ② Coagulation function. Compared with preoperative indexes, the prothrombin time (PT) at 24 h after operation in laparoscopy group and laparotomy group were both shorter (P<0.05), but there was no significant difference in activated partial thromboplastin time (APTT) and international normalized ratio (INR) between the 2 time points (before operation and 24 h after operation) in both 2 groups (P>0.05). Both at 2 time points (before operation and 24 h after operation), there was no significant difference in PT, APTT, and INR between 2 groups (P>0.05). ③ Fibrinolysis indexes. Compared with preoperative indexes, the fibrinogen (FIB) and D-dimer at 24 h after operation in laparoscopy group and laparotomy group were higher (P<0.05). The FIB and D-dimer at 24 h after operation in laparoscopy group were both higher than those of laparotomy group (P<0.05). ④ Follow-up results. There was no significant difference in metastasis rate, recurrence rate, and mortality between the 2 groups (P>0.05), but the incidence of thrombus was higher in laparoscopy group than that of laparotomy group (P<0.05). Conclusions In the treatment of patients with gastric cancer, laparoscopic surgery has the advantages of less trauma, less blood loss, less complications, and so on. Laparoscopic surgery and open surgery both can lead to hypercoagulable state, but the effect of laparoscopic surgery is stronger than open surgery.