Purpose:To investigate the clinical value of urodynamics test for benign prostatic hyperplasia (BPH).Method:Through urodynamics test for 48 cases of BPH,we had found 3 were no BOO, 6 were suspicious BOO, 39 were various degrees of BOO.Among them,9 were complicated with DI acontractile detrusor 2, high compliance bladder 6 lower compliance bladder.Results:Using different treatment methocls such as TURP,retropubic prostatectomy cystostomy and medical treatment we have got better resucts.Conclusion:Urodynamics test was an objective index todetermine whether patients need operation. Drain urine,neostigmine bromide and galanthamine were effective methods to deal with acontractile detrusor.