BackgroundTo investigate the effect of serum aspartate transaminase/alanine transaminase (AST/ALT) on the risk of prostate cancer.MethodsA total of 404 patients undergoing prostate biopsy from April 2016 to July 2019 were enrolled. One hundred and ninety‐four patients with prostatic cancer (PCa) were diagnosed by pathology. Two hundred and ten patients were diagnosed with benign prostatic hyperplasia (BPH). Multivariate logistic regression was used to analyze the effect of AST/ALT ratio and other factors on the incidence of PCa.ResultAST/ALT ratio was significantly higher in PCa than in BPH patients (OR 2.313, 95%CI 1.337‐4.003, P = .002). ROC curve indicated that the best cutoff was 1.155 in predicting the incidence risk of PCa. The age of PCa patients is higher than BPH patients (OR 1.054, 95%CI 1.027‐1.082, P < .001). We also found that platelets were lower in PCa than in BPH patients. Multivariate analysis showed that AST/ALT ratio could be used as an independent predictor to assess the incident risk of PCa(OR 1.043, 95%CI 1.014‐1.072, P = .003). However, AST/ALT ratio did not predict the incidence in high‐risk or low‐risk PCa.ConclusionAST/ALT ratio was an independent factor in predicting the incidence of PCa. When the level of AST/ALT ratio in serum raised, the incidence risk of PCa was significantly increased, which was helpful for the clinical diagnosis of PCa. We still needed a multicenter study to verify the role of AST/ALT ratio in the development of PCa.