Abstract: Objective： To study the preclinical cardiac electrophysiology physiological characteristics of Salvianolate for injection(ZDDY) and the cardiac safety of ZDDY was evaluated. Methods：In vivo， in vitro ECG and intracellular action potential recording techniques were used to analyze the P-R，QRS，QTs and heart rate(HR). Recording of hERG current from HEK cell line cloned with hERG cDNA. Results：PR interval of guinea pigs in vivo was prolonged that ZDDY was given by 460.0 mg?kg-1， prolonged from (61.0±2.8) ms to (70.9±0.9 ms) (P<0.05， n=12)， while QRS duration was significantl prolonged from (15.3±1.8) ms to (17.0±2.1) ms (P<0.05， n=12) . ECG of guinea pigs in vitro showed that after perfusion of 0.51 mg?mL -1ZDDY， heart rate (HR) of guinea pigs in vitro was significantly slowed down from (177.3±11.1) bpm to (152.0±1.7) bpm (P<0.05， n=6)， and heart rate of washout group was slightly restored.There was non effect of various concentrations of ZDDY on the action potential APD50， APD90 and action potential amplitude (APA). ZDDY inhibited the hERG currents with the IC50 of （10.8±0.6）mg?mL -1.Conclusion： The Clinical dose of ZDDY was found safe for heart of in vivo guinea pig， and no cardiac adverse events was observed. But ZDDY might slow the in vitro heart rate at high-doses.