Abstract: Objective To analyze the correlation between the change of the blood coagulation indexes and the clinical stages of the stomach cancer, the lymph node metastasis, the depth of tumor invasion through the data of the gastric cancer patients’ PT (plasma prothrombin time), Fib (fibrinogen), TT (thrombin time) and APTT (activated clotting time live enzymes) and DD (D - dimer). Methods The group of 50 patients with gastric cancer who were in the hospital from May 2015 to September 2018 are taken as an observation, 50 healthy physical examination as a control. The solidification methods are used to detect PT, Fib, TT and APTT. DD is measured by immune turbidimetry to analyze the correlation between the change of the blood coagulation indexes and the clinical stages of the stomach cancer, the lymph node metastasis, the depth of tumor invasion. Results The observation group’s Fib and DD level was higher than the control group’s (P < 0.05). TheⅡ, Ⅲ and Ⅳ period Fib, DD level in patients with gastric cancer group was higher than Ⅰ period group (P < 0.05). Compared with the control group, N0 group had higher Fib and DD levels in gastric cancer patients (P<0.05). Compared with the N0 group, the Fib and DD levels of patients with gastric cancer in the n1-3 group was higher (P<0.05). Compared with the control group, the level of Fib in T1 patients was higher (P<0.05). Compared with t1-stage patients, t2-t4 patients had higher levels of Fib and DD (P<0.05). Conclusions the coagulation function is poor in patients with gastric cancer, and it is related to the clinical stage, lymph node metastasis and the depth of tumor invasion.