OBJECTIVE： To investigate the effects of bisoprolol on the QRS-T angle in ACS patients after emergency PCI. METHODS： 100 ACS patients who took PCI were randomly divided into conventional group （50 cases） and bisoprolol group （50 cases）， and other 50 coronary stenosis＜50％ were selected as control group. Patients in conventional group received Aspirin enteric-coated tablet 300 mg 30 min before PCI， orally， once a day+Clopidogrel bisulfate tablet 600 mg， orally， once a day， 100 mg aspirin was given in the night after PCI， orally， once a day+clopidogrel 75 mg， orally， once a day+Atorvastatin calcium tablet 20 mg， orally， once a day， and other conventional treatment. Bisoprolol group was additionally given Bisoprolol fumarate tablet 5 mg， orally， once a day. Control group received Aspirin enteric-coated tablet+Clopidogrel bisulfate tablet+Atorvastatin calcium tablet （the same dosage and usage as conventional group）. All patients were treated for 12 months. The frontal QRS-T angle before and after operation， Gensini score in all groups the incidence of MACE in 1-year was followed-up. RESULTS： After operation， QRS-T angle in bisoprolol group was significantly lower than before and conventional group， but higher than control group， with statistical significances （P＜0.05）， there was no significant difference in conventional group before and after operation （P＞0.05）， so as the Gensini score in 2 groups （P＞0.05）. The incidence of MACE in bisoprolol group was significantly lower than conventional group， with statistical significance （P＜0.05）. The QRS-T angle in bisoprolol group（preoperative－postoperative） negatively correlated with the incidence of MACE （r＝－0.339，P＝0.057）. MACE risk decreased 8％ if frontal QRS-T angle increased 1° in bisoprolol group （P＝0.041）， MACE risk increased 32％ if Gensini increased 1 score（P＝0.035）. CONCLUSIONS： Based on conventional treatment， early use of bisoprolol can reduce the QRS-T angle and the MACE risk， and the decrease degree of frontal QRS-T angle is correlated with the incidence of MACE.