Objective To explore the changes of blood supply to the benign prostatic hyperplasia and its clinical significance. Methods A total of 130 patients with benign prostatic hyperplasia underwent transrectal ultrasound prostate examination and the size of prostate was measured. Patients were divided into ≤25 g group, 26-50 g group, 51-75 g group, and ≥76 g group according to the estimated weight of prostate. The inner diameter of urethral artery of prostate, velocity of maximum flow (Vmax), pulsatility index (PI), and resistance index (RI) of 4 groups were measured and statistically processed. Among 130 patients, 27 of them underwent the prostatic artery embolization. The variations of inner diameter of urethral artery of prostate, Vmax, PI, RI, and the weight of prostate before and after the prostatic artery embolization were compared. Results The differences of inner diameter of urethral artery of prostate, Vmax, PI, and RI of patients among 4 groups or in the same group were statistically significant (P<0.05). The inner diameter of urethral artery of prostate, Vmax, PI, and RI were positively correlated with the weight of prostate. Three months and one year after the prostate artery embolization, reexaminations showed that values of the inner diameter of urethral artery of prostate, Vmax, PI, RI, and the weight of prostate were significantly smaller and the differences were statistically significant (P<0.05). Conclusion For benign prostatic hyperplasia, the blood supply is significantly increased. The values of velocity of blood flow, inner diameter, and resistance of the urethral artery of prostate are larger. Blocking the transurethral prostatic artery can significantly reduce the blood supply and the size of prostate, and is helpful for relieving the lower urinary tract obstruction.