In recent years, the incidence of prostate cancer in China has shown an increasing trend year by year due to the aging of the social population, environmental and lifestyle changes. In China, 68% of new cases of prostate cancer are metastatic patients at first diagnosis, and almost all patients will progress to destructive resistant prostate cancer (CRPC) after 2-3 years of endocrine therapy. Once patients enter the CRPC stage, the disease tends to progress rapidly and the prognosis is poor. Therefore, CRPC has long been a key challenge in the treatment of prostate cancer worldwide, and finding appropriate tumor markers to predict the prognosis of patients with CRPC has also become a focus of research. Prostate-specific antigen (PSA), which is often used as an important indicator for early diagnosis and monitoring of biochemical recurrence or disease progression, has been poorly documented in predicting prognosis in patients with CRPC. Circulating tumor cells (CTCs) are formed in malignant solid tumors during the proliferation process as the tumor lesion increases in size and the tumor cells shed from the primary lesion, break through a series of barriers, and then move chemotactically into the lymphatic vessels and blood circulation. Most of the tumor cells entering the circulatory system die within a short period of time, but only a very small number of tumor cells with high vitality and high metastatic power survive in the circulatory system, gather together to form microscopic cancer thrombi, and develop into metastatic foci under certain conditions. Previous studies about CTC at home and abroad were mostly limited to CTC counting, and few studies involved CTC marker detection. from January 2013 to June 2014, the team from the Department of Urology, Cancer Hospital of Fudan University collected peripheral blood specimens from 70 mCRPC patients and 20 healthy individuals, and completed CTC counting using the CellSearch method, using The stem cell marker detection of CTC was completed by Realtime-PCR with Taqman probe. We found that the combined application of CTC counting and stem cell marker assay could better predict the prognosis of patients with mCRPC than the counting method alone. patients with positive stem cell marker expression in CTC were less effective to docetaxel combined with prednisone treatment in the former compared to negative patients.