Aim To investigate the correlation between platelet crit (PCT) and global registry of acute coronary events (GRACE) score in patients with non-ST-segment elevation myocardial infarction (NSTEMI) and its predictive value for severe lesions. Methods The clinical data of 193 patients with NSTEMI in Wuhan Yaxin General Hospital from January 2019 to January 2020 were analyzed retrospectively. According to the results of coronary angiography, the patients who involved three coronary arteries and/or left main artery were severe lesion group (96 cases), and the rest were non-severe lesion group (97 cases). Spearman correlation analysis was used to observe the correlation between PCT and GRACE score, and receiver operating characteristic (ROC) curve was used to analyze the predictive value of PCT for severe lesions of NSTEMI. Results PCT in severe lesion group was significantly higher than that in non-severe lesion group ((0.32%±0.05%) vs (0.24%±0.04%), P＜0.001), and platelet count (PC) was significantly lower than that in non-severe lesion group ((180.46±19.46)×10⁹/L vs (212.54±30.17)×10⁹/L, P＜0.001). Spearman correlation analysis showed that no matter the non-severe lesion group or the severe lesion group, PCT was positively correlated with GRACE score (r＝0.288, P＝0.004; r＝0.777, P＜0.001), while PC was negatively correlated with GRACE score (r＝－0.846, P＜0.001; r＝－0.822, P＜0.001). For the area under curve of ROC, PCT was the largest (0.858), followed by PC (0.802). The critical value of PCT was 0.275, the sensitivity was 81.3%, and the specificity was 84.5% in the diagnosis of NSTEMI severe lesions. Conclusion PCT is positively correlated with GRACE score, and it has a better predictive value for NSTEMI severe lesions.