This study investigated the intervention effect of Guanxinning Tablet on human umbilical vein endothelial cells (HUVECs) injury induced by oxidized low density lipoprotein (ox-LDL), providing experimental basis for Guanxinning Tablet in the treatment of atherosclerosis-related diseases. Under the damage of HUVECs by ox-LDL, the cell viability was detected by CCK-8 (cell counting kit-8) assay; lactate dehydrogenase (LDH) in the cell culture supernatant was detected by the corresponding kit; the cell morphology of different groups was observed by common phase contrast microscope; reactive oxygen species (ROS) and NO levels in the cells were detected by DCFH-DA and DAF-FM DA probes, respectively; monocyte adhesion assay was used to detect the recruitment of THP-1 in HUVECs, and TMRM dye was used to detect the level of mitochondrial membrane potential; interleukin-6 (IL-6), intercellular adhesion molecule-1 (ICAM-1) and monocyte chemoattractant protein-1 (MCP-1) secretion in the cells was detected by ELISA assay. The results showed that Guanxinning Tablet had a concentration-dependent proliferative effect on HUVECs. Under the stimulation of 100 μg·mL^-1 ox-LDL, the morphology of endothelial cells was significantly changed. At this time, NO level was significantly decreased, ROS level was significantly increased and accompanied by a decrease in mitochondrial membrane potential. The recruitment of THP-1 cells by endothelial cells and IL-6, ICAM-1 and MCP-1 were also significantly increased, resulting in oxidative stress and inflammatory injury. Guanxinning Tablet and its composed extracts could significantly improve cell morphology, increase NO level, decrease ROS production, and also reduce the secretion of inflammation-related proteins IL-6 and MCP-1. Salvia miltiorrhiza and Ligusticum striatum DC. have significant synergistic effects on NO. Among them, salvianolic acid B and salvianic acid A exerted the main effects, and the combined efficacy of salvianic acid A and ferulic acid was superior to that of single administration. The above results showed that Guanxinning Tablet and their active substances had the effects of improving endothelial basal function, resisting oxidative stress, and alleviating inflammatory injury, and Salvia miltiorrhiza and Ligusticum striatum DC. synergized, which may be related to their regulation of oxidative stress and inflammation and have application prospects in the treatment of atherosclerosis-related diseases.