Abstract: ob＜x＞jective To investigate the diagnostic value of platelet parameters in patients with gastric cancer and its relationship with clinicopathological features. Methods 391 patients with gastric cancer treated in the Affiliated Hospital of Xuzhou Medical University from December 2015 to December 2020 were taken as the research ob＜x＞ject, and 149 healthy people who underwent physical examination in the hospital in the same period were taken as the control group. The differences of platelet parameters between the two groups and the relationship between preoperative platelet parameters and clinicopathological data in gastric cancer group were analyzed retrospectively. Meanwhile,ROC curve was used to evaluate the diagnostic efficacy of platelet parameters in gastric cancer. Results PLT in gastric cancer group was significantly higher than that in control group, while MPV, PDW and P-LCR were significantly lower than those in control group (P < 0.05). PLT and PCT in gastric cancer group increased with the increase of tumor maximum diameter, degree of differentiation, depth of invasion, TNM stage, CEA, CA19-9 and lymph node me＜x＞tastasis (P < 0.05); With the increase of maximum tumor diameter and TNM stage, PDW decreased in gastric cancer group (P < 0.05). PLT and PCT have diagnostic value for gastric cancer, and PLT has high diagnostic efficiency. Conclusions