Aim To investigate the correlation between myeloperoxidase（MPO） and coronary slow flow（CSF）. Methods Through corrected TIMI frame count（CTFC）, the randomly selected 600 patients without coronary artery stenosis by coronary angiography （CAG） were screened out of 52 patients of CSF as the study group, the other randomly selected 52 patients without CSF as the control group. Plasma levels of MPO and other blood biochemical index were obtained in all participants, and analysis of the difference between the two groups, logistic regression analysis was used to screen the risk factors of CSF. Results Baseline values were similar in two groups MPO levels of the CSF group were significantly higher than control group（93.70±37.75 μg/L vs 26.76±6.20 μg/L, P<0.001）, the difference was statistically significant Logistic regression analysis showed that high plasma MPO level was related to CSF（OR1.23,P0.001）.