This paper is aimed to assess the diagnostic value of MRI versus 99Tcm-methylene diphosphonate (99Tcm-MDP) bone scan (BS) for osseous metastases in patients with prostate cancer. The computer-based retrieval was conducted on PubMed, EMBASE, EBSCO, Web of Knowledge, the Cochrane Library and Ovid data bases to search for trials about diagnosing osseous metastases of prostate cancer with MRI and 99Tcm-MDP BS. Selected with time acceptance and time exclusion criteria, the data quality were evaluated with QUADAS quality assessment tool and collected. We used the Meta-Disc software to conduct meta-analysis, and then calculated the pooled sensitivity, specificity and diagnostic odds ratio (DOR), drew the summary receiving operating characteristic (SROC) curve, and measured the area under curve (AUC) and Q* value. Then five studies were included, involving 353 patients. The pooled sensitivity of MRI and BS was 0.95 (95% CI 0.90~0.98) and 0.67 (95% CI 0.58~0.75), respectively. The pooled specificity was 0.97 (95% CI 0.94~0.99) and 0.88 (95% CI 0.83~0.91), respectively. The pooled DOR was 402.99 (95% CI 119.05~1 364.15) and 23.85 (95% CI 1.32~431.48), respectively. The AUC was 0.990 1 and 0.624 1, respectively. The Q* was 0.958 7 and 0.593 8. It can well be concluded that MRI is more effective than 99Tcm-MDP BS in the diagnosis of osseous metastases in patients with prostate cancer.