Objective To explore the effects of Panax notoginseng saponins (PNS) on the proliferation, apoptosis, migration and invasion of osteosarcoma cell line U2OS and its possible molecular mechanism. Methods Human osteosarcoma cell line U2OS was cultured and treated with (0, 200, 400, 600, 800, 1000) μg/mL PNS. The proliferation of U2OS was detected by CCK-8 method. Annexin V-FITC/PI double labeling combined with flow cytometry was used to analyze cell apoptosis. Clone formation assay was used to detect the clone formation ability of the cells. Transwell invasion assay was performed to detect cell invasion. Transwell migration assay and wound-healing assay were used to determine cell migration. Western blotting was used to detect the expression of Notch1 and downstream protein Hes1 in U2OS cells. Results Compared with the control group, PNS could inhibit the proliferation of U2OS cells and the formation of clonal plaques, increase cell apoptosis rate, weaken the ability of migration and invasion and decrease the expression levels of Notch1 and Hes1 in the cells in a dose-dependent manner. Conclusion PNS can significantly inhibit the proliferation, migration and invasion and promote cell apoptosis of U2OS cells by blocking Notch1 signaling pathway.