Objective To determine the effects of Yinxing Mihuan (YM) oral solution on the proliferation, migration, tubule formation and protein expression of vascular endothelial growth factor (VEGF) and CD31 in rat cardiac microvascular endothelial cells (CMECs) and whether YM promotes angiogenesis in vitro. Methods CMECs were cultured and divided into a control group and YM high dose (2. 6 mg / mL), YM medium dose (1. 3 mg / mL) and low dose (0. 6 mg / mL) YM groups. The cell counting CCK-8 assay was used to measure proliferation, and the scratch test was used to detect the migration of CMECs. A Matrigel-based angiogenesis assay was used to detect tube formation by CMECs, and Western blot were used to detect the expression of VEGF and CD31. Results Compared with that in the control group, the high, medium and low YM doses significantly promoted the proliferation of CMECs, and the proliferation rate in YM high dose YM group was significantly higher than that in YM medium and low dose YM groups. Six hours after scratching the CMEC monolayer, the migration rate of CMECs in YM high dose YM group was significantly higher than that in the control group; the migration rates of CMECs in YM medium and low dose YM groups were increased, but there was no significant difference compared with the control group. Twenty-four hours after scratching the monolayer, the migration rates of CMECs in YM high, medium and low dose groups were significantly increased compared with that in the control group. The Matrigel matrix number, area and cross points for CMECs in YM high dose group were significantly improved compared with those in YM medium and low dose YM groups. Compared with that in the control group, the expression of VEGF and CD31 in YM high and medium dose YM groups was significantly increased. Conclusions YM can promote proliferation, migration, angiogenesis and expression of VEGF and CD31 proteins in CMECs in vitro. These effects were dose-dependent, suggesting that YM has a significant ability to promote angiogenesis.