To investigate the expression of SIX2 in osteosarcoma and its effect on angiogenesis and reversal of doxorubicin resistance. Methods Tissue specimens of 105 patients who underwent surgical resection of osteosarcoma in our hospital from March 2019 to December 2021 were collected. SIX2 expression and microvascular density (MVD) count in osteosarcoma were detected by immunohistochemistry. The expression level of SIX2 mRNA in osteosarcoma was detected. Human osteosarcoma cell line MG-63 was divided into MG-63 group, si- NA group, si- SIX2A group. Adriamycin-resistant osteosarcoma cells MG-63/R were divided into MG-63/R group, si- NB group and si- SIX2B group. MTT assay, cloning assay, flow cytometry and Transwell assay were used to detect cell resistance, cell proliferation, cell apoptosis and cell invasion.Results In osteosarcoma tissue, the positive expression of SIX2 increased with the increase of MVD value (P＜0.05). The positive expression of SIX2 in osteosarcoma tissue was correlated with TNM stage, soft tissue infiltration and distant lymph node metastasis (P＞0.05). Compared with MG-63 group, the angiogenesis ability of cells in si-SIXA group was significantly decreased (P＜0.05). Compared with MG-63/R group, the IC50, cell clone number and cell invasion ability of si-SIX2 B group cells were significantly decreased, the apoptotic capacity was significantly increased, and the reversal fold of the cell resistance index was 2.51 times (P＜0.05).Conclusion SIX2 was highly expressed in osteosarcoma tissues, and the tumor angiogenesis ability also increased with the increase of SIX2 expression. Inhibition of SIX2 expression can effectively inhibit the formation of osteosarcoma tissue and reverse the doxorubicin resistance of osteosarcoma cells