Objective：To observe the pathological responses of chronic inflammation and urodynamic changes of the rats with chronic nonbacterial prostatitis（CNP）. Methods：Twenty male SD rats were equally divided into 4 groups（n=5）. After the experimental CNP rat model was established，the urodynamical recordings and histopathological analysis were done on the 45th，60th d and 90th d. Re－sults：Prostatic inflammation was induced in model group. Mic－turition volume（MV），maximal micturition volume（Max MV），vesical compliance（VC） and micturition interval（MI） were sig－nificantly deceased in model group than in normal control group on the 45th d （P<0.05）. Post void residual（PVR） and maximal bladder pressure were increased in model group than in normal control group on the 60th d（P<0.05）. MV was decreased，PVR and VC were increased and MI was shortened in model group than in normal control group on the 90th d （P<0.05）. Conclusion：Urodynamic changes are existed in CNP model and its mechanism needs further study.