The morbidity and mortality of prostate cancer have been increasing recently, and the comprehensive treatment for prostate cancer is unable to achieve satisfactory outcomes. Quercetin is a natural flavonoid compound that has attracted increased interest and attention due to its anticancer activity. In vitro and in vivo studies have verified that quercetin effectively inhibits prostate cancer via various mechanisms. Clinical trails concerning the pharmacokinetics and application of quercetin in humans have also obtained promising results. Meanwhile, epidemiologic studies have demonstrated a negative association between quercetin intake and prostate cancer incidence and have suggested a chemopreventive effect of quercetin on prostate cancer that has been exhibited in animal experiments. The main issue concerning quercetin utilization is its low bioavailability. Therefore, solutions to the issues concerning its use such as alteration of the molecular structure and combination therapy are in the exploratory stage. In the present review, the most important aspects of chemotherapeutic and chemopreventive effects, mechanisms and clinical application potential of quercetin in prostate cancer are summarized.