A total of 30 C57B6 mice were randomly divided into sham operation group，SSS group，and Shenxianshengmai Oral Liquid treatment （SXSM） group， and there were 10 mice in each group. The SSS mice model was established by pumping angiotensinⅡ（ANGⅡ） with the Alzet osmotic pressure pump.The mice in SXSM group were given 0.2 mL of Shenxianshengmai Oral Liquid per day for 28 d. The electrocardiogram of the mice in various groups was observed and the heart rates were analyzed； HE and Masson staining methods were used to observe the pathomorphology of sinoatrial node tissue of the mice in various groups，immunofluorescence method was uesd to detect the levels of ROS and HCN4 in sinoatrial node tissue of the mice in various groups； Real-time fluorescence quantitative PCR （RT-qPCR） method was used to detect the expression levels of voltage-gated Na⁺α subunit （SCN5A）， L-type voltage dependent calcium channels α 1C subunit protein （CACNα1C） and voltage dependent calcium channel α1G subunit protein （CACNα1G） mRNA in sinoatrial node tissue of the mice in various groups； Western blotting method was used to detect the expression levels of SCN5A，CACNα1C，CACNα1G，and HCN4 proteins in sinoatrial node tissue of the mice in various groups.

Compared with sham operation group， the heart rate of the mice in SSS group was decreased significantly （P<0.05）， the cells were dissolved and necrotic， there was no nucleus， and there was a large number of connective fiber tissue； the ROS level in sinoatrial node tissue was increased （P<0.05），the HCN4 level in sinoatrial node tissue was decreased （P<0.05）， the expression levels of SCN5A mRNA and protein in sinoatrial node tissue were decreased significantly （P<0.05），the expression levels of CACNα1C and CACNα1G mRNA and proteins in sinoatrial node tissue were increased significantly （P<0.05），and the expression level of HCN4 protein in sinoatrial node tissue was decreased significantly （P<0.05）；compared with SSS group， the heart rate of the mice in SXSM group was increased significantly（P<0.05），a small amount of connective fiber tissue showed hyperplasia， partial of the cells showed necrosis and dissolution， the ROS level in sinoatrial node tissue was decreased （P<0.05），the HCN4 level in sinoatrial node tissue was increased （P<0.05），the expression levels of SCN5A mRNA and protein in sinoatrial node tissue were increased （P<0.05），the expression levels of CACNα1C and CACNα1G mRNA and proteins in sinoatrial node tissue were decreased significantly （P<0.05），and the expression level of HCN4 protein in sinoatrial node tissue was increased significantly （P<0.05）.

Shenxianshengmai Oral Liquid can increase the heart rate， inhibit the release of ROS in sinoatrial node tissue of the SSS mice， and inhibit the fibrosis of the sinoatrial nodes. The mechanism is related to the regulation of HCN4 ion channels.