ObjectiveTo investigate the therapentic effect and safety by use of Metoprolol to control patients ,heart rate in off-pump coronary artery bypass graft (OPCAB). MethodsAnalyse the dates of 40 OPCABG patients in anesthetic stage. ResultsIn all of the cases,when patients were treated with venous injection of Metoprolol, the heat rate obviously decreased 1 minutes later( P ＜ 0.01 ). the heat rate decreased significant to( 69.2 ± 10. 8)times/min 3 minutes later, Compared to the heat rate ( 85.1 ± 13.5) times/min of pretherapy there was statistical significance. the heat rate decreased to nadir(63.0 ± 6.2) times/min 10 minutes later. While it raised gradnally 30 minutes later,but patients'heat rate nulli-exceed. it of pretherapy. On post-treatment of 3min、5min、 10min、30min, The MAP nulli-genic marked change. ConclusionMetoprolol could control effectively patients,heat rate in OPCAB and keep hemodynamics stable.