Abstract: The majority of prostate cancer (PCa)-induced deaths is due to the development of metastatic disease, 80% of which is primarily localized in the bone. The types of bone metastasis of PCa are mainly osteoblastic or osteoclastic lesions. What triggers PCa metastasis to the bone and what causes osteoblastic and osteoclast lesions remain unanswered. A major contributor to PCa metastasis is the host microenvironment. Here, we mainly discuss how primary tumor microenvironment affects the occurrence and mechanism of bone metastasis in prostate cancer. The mechanisms and effects of secretory factors, secretory proteins, immune cells, osteoblasts, osteoclasts and other secreted factors on bone metastasis of prostate cancer will be discussed and summarized.