Objective: evaluate the improvement of Peak Flow Rate (Qmax) after Bipolar resection of the prostate (BITURP) for benign prostatic hyperplasia (BPH). Patients and method: 64 patients with BPH who underwent BITURP from November 2012 to June 2013 at No.103 Hospital. Values of Qmax were taken at the points of time: before surgery, just after urethral catheter removed, 1 month later, 3 months later. Method: prospective cross-sectional study, longitudinal follow-up. Results: There was 100 percent patients of Qmax 12 ml/s before surgery. After surgery 3 months, 100 percent patients had Qmax 15ml/s and the mean increase was 187.5 percent, with an absolute mean improvement of 13.52 ml/s. Its was significant statistically with p 0.001. Conclusion: Qmax index improved significantly after bipolar transurethral resection of the prostate.