Objective：This study aims to investigate the influencing factors of coronary slow flow（CSF）. Methods：The clinical data of 94 patients with CSF（CSF group）and 94 cases without CSF（control group）who underwent coronary angiography were recorded. The influencing factors of CSF and predictive value of platelet distribution width（PDW）for CSF were analyzed. Results：The ratio of diabetes of CSF group was higher than that in control group（P＜0.05）.The platelet（PLT），plateletocrit（PCT），mean platelet volume（MPV），platelet distribution width（PDW）and fasting plasma glucose（FPG）were different between the two groups（P＜0.05）. Multivariate logistic regression analysis showed that diabetes and PDW were the influencing factors of CSF（P＜0.05）. PDW in the CSF group increased significantly with increasing vessel involvement. ROC curve showed that the AUC of PDW predicting CSF was 0.675，optimum truncation value was 13.85%，sensitivity was 51.1% and specificity was 80.9%. Conclusion：Diabetes and PDW are the influencing factors of CSF and PDW may predict the occurrence of CSF.