Objective：This study aims to explore the effect of exosome of prostate cancer cells on the osteoblast differentiation. Methods：The ExoQuick-TC kit and ultrafiltration are adopted to isolate and purify exosomes from prostate cancer cell lines. The exosomes will be characterized by marker CD63，and observed through electron microscopy. Extract total RNA from pre-osteoblasts treated by exosomes of prostate cancer cells；then expressions of Osx，Runx2 and Alp were detected by real-time PCR. Osx and Runx2 are the biomarker of early osteogenic differentiation and Alp is the biomarker of metaphase osteogenic differentiation. Furthermore，osteogenic differentiation were ohserved by using ALP and ARS staining. Results：Prostate cancer cell exosomes can enter pre-osteoblasts. Compared to control cells，the expression of Osx，Runx2 and Alp are decreased in pre-osteoblasts cells treated with prostate cancer cell exosomes（P < 0.05）. The staining results showed that osteogenic differentiation was inhibited. Conclusion： Prostate cancer cells secrete exosomes that can act on pro-osteoblasts and inhibit osteoblast differentiation.