Objective To analyze the changes of serum fatty acid synthase (FAS),carcinoembryonic antigen (CEA) and carbohydrate antigen 72-4 (CA72-4) in patients with gastric cancer and its clinical diagnostic value.Methods Forty five patients with gastric cancer and 45 patients with benign gastric cancer treated in our hospital from January 2016 to December 2016 were enrolled in this study.Forty five healthy subjects were enrolled in this study.The levels of FAS,CEA,and CA72-4 in three groups were analyzed.Results The levels of FAS,CEA,and CA72-4 in patients with gasttric cancer [(12.73 ± 5.48) mg/L,(31.36 ± 14.51) ng/ml,and (39.32 ± 18.76) U/ml] were significantly higher than those in benign gastric cancer group [(2.26 ± 1.15) ng/L,(3.24 ± 1.47) ng/ml,and (3.75 ± 1.69) U/ml],and normal control group [(1.83 ± 0.92) mg/L,(2.71 ± 1.54) ng/ml,and (3.13 ± 1.82) U/ml] (P ＜ 0.05).FAS,CEA,and CA72-4 levels in patients with lymph node metastasis of gastric cancer [(13.58 ± 6.09) mg/L,(6.25 ± 11.54) ng/ml,and (41.31 ± 13.67) U/ml] were significantly higher than those without lymph node metastasis [(9.21 ± 5.42) mg/L,(28.38 ± 9.72) ng/ml,and (26.75 ± 11.86) U/ml] (P ＜ 0.05).The sensitivity of FAS,CEA,and CA72-4 in patients with gastric cancer was significantly lower than that in combined detection,the specificity of FAS,CEA,and CA72-4 in patients with gastric cancer was significantly higher than that in combination test (P ＜ 0.05).The sensitivity of FAS,CEA,and CA72-4 in patients with lymph node metastasis was significantly lower than that in combination test,and the specificity of FAS,CEA and CA72-4 was significantly higher than that of combined detection (P ＜ 0.05).Conclusions FAS,CEA,and CA72-4 can be used as indicators of gastric cancer and diagnosis of lymph node metastasis.Combined detection of three indexes can improve the diagnostic sensitivity and have good clinical significance.