Aim To investigate the accuracy of platelet-lymphocyte ratio （PLR） predicting left ventricular systolic dysfunction （LVSD） in patients with non ST-elevation acute myocardial infarction （NSTEMI）. Methods 98 NSTEMI patients in our hospital from January,2013 to January,2014 were selected as the observation group,and another 30 ST-elevation acute myocardial infarction （STEMI） patients and 30 healthy persons with the same age in the same period were selected as the control group. Platelets and lymphocyte count of 3 groups the day after being included in the experiment were detected and PLR was calculated. All the patients in the observation group had no LVEF and were followed up every 3 months,and the total follow up period was 1 year. In follow up,ejection fraction （EF） and left ventricular end diastolic volume （LVEDV） of the observation group were tested by cardiac ultrasound and divided into LVSD group （EF≤50%,n63） and non-LVSD group （EF＞50%,n35） according to EF. PLR of LVSD group and non-LVSD group were compared. Pearson correlation analysis was used to analyze the relationship between PLR and LVSD incidence of NSTEMI patients and ROC curve was used to analyze the predict accuracy of PLR on LVSD of NSTEMI patients. Results PLR of observation group and STEMI group had no statistical significance （P＞0.05）. Compared with control group,platelet count and PLR of observation group was higher while lymphocyte count of observation group was lower,and the difference was statistically significant （P<0.05）. The lowest,highest and average PLR of LVSD group were 66.86,744.68 and 169.78±44.96 respectively,which were higher than the 22.68,324.55 and 100.47±32.67 of the non-LVSD group,and the difference had statistical significance （P<0.05）. Pearson correlation analysis results showed that PLR and LVSD incidence of NSTEMI patients was significantly and positively correlated （r0.876,P<0.01）. Area under the ROC curve,sensitivity,specificity and accuracy of PLR （474.58） predicting LVSD of NSTEMI patients were high,which mean that prediction value of PLR on LVSD of NSTEMI patients was good. Conclusions PLR in NSTEMI patients was significantly elevated and associated with the incidence of LVSD of NSTEMI patients. Predict value of PLR on LVSD of NSTEMI patients was good and prediction value of PLR value as 474.58 was the best,thus NSTEMI patients with high PLR should be alert to LVSD and intervened as early as possible in order to improve the prognosis of patients.