Objective To investigate the clinical characteristics of acute anterior myocardial infarction complicated by complete atrioventricular block (CAVB). Methods A total of 885 patients with acute anterior myocardial infarction were enrolled, and were divided into CAVB group (complicated by CAVB, n=19, 2.1%) and non-CAVB group(not complicated by CAVB, n=866, 97.9%). The serum peak levels of creatine kinase and its isoenzyme, BNP level, left ventricular ejection fraction (LVEF), Killip heart performance stage, coronary artery lesion feature and hospital mortality were observed, and pathological factors of CAVB and their impact on prognosis were analysed. Results Compared with patients in nonCAVB group, those in CAVB group had significantly higher serum peak levels of creatine kinase and its isoenzyme [（1 804.5±65.4）U/L vs （1 251.3±46.7）U/L，（155.8±25.6）U/L vs （104.3±19.1）U/L，P<0.05 for both], significantly higher BNP level [（1 254.4±55.3）pg/mL vs （432.4±78.5）pg/mL，P<0.05], poorer Killip heart performance stage （P<0.05）, significantly lower LVEF [（40.5±4.6）% vs （51.2±6.9）%，P<0.05], more severe coronary artery lesions （P<0.05）and significantly higher hospital mortality （63.2% vs 2.4%，P<0.05）. Conclusion Patients with acute anterior myocardial infarction complicated by CAVB may have more severe coronary artery lesions, more extensive infarction area, worse heart performance and higher in hospital mortality.