Objectives：The purpose of the study is to assess the variation of left ventricular function and ischemic mitral regurgitation volume before and after percutaneous coronary intervention (PCI) by echocardiography. Thus we can improve the understanding of IMR and help clinical decision make. Methods：We evaluated the left ventricular function and IMR before and after PCI by echocardiography. Then divided the patients into two groups by the variation of mitral regurgitation volume (group one: IMR volume diminish or increase less than 15 ml; group two: IMR volume increase more than or equal to 15ml). Results：Postoperative left ventricular radial strain and ejection fraction has significant improvement in group one. And postoperative left ventricular longitudinal strain has improved compared to preoperative status. In group two, postoperative left ventricular ejection fraction has no significant improvement, whereas left ventricular end-diastolic diameter has enlarged. Conclusions：Echocardiography can evaluate left ventricular muscle function sensitively. PCI can help reduce IMR by improving left ventricular systolic function.