Objective: To analyze the diagnostic efficacy of diffusion weighted imaging (DWI) guided prostate biopsy in prostate cancer (PCa). Methods: A total of 124 patients with suspected PCa who were admitted to our hospital for different degrees of urinary tract obstruction from September 2016 to September 2019 were selected as the study subjects. DWI examination was performed before puncture, and image features were analyzed. The ROC curve of the apparent diffusion coefficient (ADC) value was drawn based on the pathological results as the “gold standard” to analyze the value of ADC in the diagnosis of benign and malignant prostate lesions. In addition, differences in the detection rate of prostate cancer between DWI targeted biopsy and systematic biopsy were compared. Results: Pathology confirmed 56 cases of malignant lesions (45.2%), the remaining 68 cases of benign prostatic hyperplasia (54.8%); ADC value of patients with PCa under DWI was significantly lower than that of patients with BPH [(0.810±0.091) mm2/s vs (1.499±0.293) mm2/s, t=16.878, P<0.05]; ROC curve analysis showed that the AUC of ADC value in the diagnosis of benign and malignant prostate tumors was 0.869, and the sensitivity and specificity of ADC value =1.091 mm2/s were 83.9% and 76.5%, respectively; The number of DWI targeted biopsy needles was significantly lower than that of TRUS system, and the proportion of tumor tissue in DWI targeted biopsy positive needles was significantly higher than that in TRUS system, with statistically significant differences (P<0.05). Conclusion: DWI can qualitatively and quantitatively differentiate and diagnose benign and malignant prostate lesions, and DWI targeted prostate biopsy can achieve similar tumor detection rate through fewer puncture needles and provide more tumor tissue in the positive needle compared with the classic system puncture.