Objective To study the influence of androgen deprivation on prostate cancer bone metastasis in nude mouse models and to explore the biological characteristics of circulating tumor cells during tumor metastasis.Methods Forty male 6-7-week old nude mice were randomly divided into two groups:the castration group and untreated normal control group.All the nude mice were injected intracardially human prostate cancer PC3-Luc-GFPcells (labeled with GFP and Luc) in a dose of 1×10⁶/50 μL/mouse to establish the bone metastasis models. The resulted cancer bone metastasis was confirmed by detection of Luc signal using a small animal optical imaging system.Bone tissue samples were fixed with 4% paraformaldehyde and pathological examination using HE staining was performed. Circulating tumor cells (CTCs) were isolated from the periphery blood collected by heart puncture.The expression of metastasis-associated molecules TOPK and RANKL of CTCs was detected by Western blot assay. Results The nude mouse model of human prostate cancer bone metastasis was successfully established. The incidence rate of bone metastasis in the castration group was 2/13(15.38%), while that of the normal control group was 5/14=35.71%. The xenograft models were prepared twice and the results of the two experiments were pooled together, showing a bone metastasis incidence rate of 11.54%(3/26) in the castration group and 37.04%(10/27) in the normal control group (P<0.05). The expressions of TOPK and RANKL of CTCs were significantly higher than that in the original prostate cancer cells.Conclusions Castration can significantly reduce the incidence of prostate cancer bone metastases in nude mouse models. Metastatic potential of CTCs is significantly higher than that of the original prostate cancer cells.