【Objective】 To explore the efficacy and safety of "ditching and ridge removal" with 450 nm semiconductor blue laser in the treatment of large volume benign prostatic hyperplasia (BPH), in order to promote the clinical application of this method. 【Methods】 A retrospective study was conducted on 30 patients with large volume BPH treated with "ditching and ridge removal" with 450 nm semiconductor blue laser in Yingsheng Branch of Tai’an Central Hospital during Sep.and Dec.2023.The laser operation time, level of hemoglobin before and after operation, bladder irrigation time after operation, urinary catheter indwelling time, postoperative hospital stay, and intraoperative and postoperative complications were recorded.The changes of international prostate symptom score (IPSS), quality of life scale (QoL) score, maximum urinary flow rate (Qmax) and post-void residual volume (PVR) were compared before and 1 month after operation. 【Results】 The volume of prostate was (104.5±14.52) mL, the laser operation time was (20.13±2.98) min, and the bladder irrigation time was (20.27±2.56) h.The catheter was removed in all patients 2 days after operation, and all patients were discharged 3 days after operation.One month after operation, the IPSS, QoL, Qmax and PVR were significantly improved as compared with those before operation (P<0.05).No complications occurred during the follow-up. 【Conclusion】 "Ditching and ridge removal" with 450 nm semiconductor blue laser is a new, safe and effective method in the treatment of large volume BPH.