[Abstract] Objective: To explore whether PDGF-BB can be transmitted through exosome and verify its angiogenic function in human osteosarcoma. Methods: Exosomes from a variety of human osteosarcoma cells were isolated. The expression of PDGF-BB in cells and exosomes was detected by WB. Exosomes derived from osteosarcoma SJSA-1 cells were co-incubated with HUVEC, and the pattern of exosomal PDGF-BB entering HUVEC was observed using Immunofluorescence and confocal scanning microscope. SJSA-1 cell lines with PDGF-BB over-expression or knockdown were constructed by lentiviral infection, and the exosomes derived from transfected SJSA-1 cells were isolated and incubated with HUVEC. Microtubule formation experiment was conducted to detect their effects on angiogenesis; SJSA-1 cell transplanted xenograft model was established in nude mice, and the exosomes derived from SJSA-1 cells with PDGF-BB over-expression or knockdown were infused into nude mice to observe their effects on tumor growth. Results: The exosomes derived from osteosarcoma cells were successfully isolated, in which a large amount of PDGF-BB was confirmed. The exosomes entered HUVEC by endocytosis. The SJSA-1 cell lines with PDGF-BB over-expression or knockdown were successfully constructed, and the corresponding exosomes were isolated. Compared with the control group, exosomes with high PDGF-BB content significantly promoted HUVEC angiogenesis (P < 0.01 , t=13.51) and tumor growth (P < 0.01 ), while exosomes with low PDGF-BB content reduced the angiogenesis ability of HUVEC (P < 0.01 , t=8.226) and inhibited tumor growth (P < 0.01 ). Conclusion: The exosomal PDGF-BB secreted by osteosarcoma cells can be directly absorbed by HUVEC and induce tumor angiogenesis, further promoting the growth of osteosarcoma.