To investigate the detrusor fibrosis and urinary dysfunction in chronic prostatitis (CP), and to investigate whether resveratrol can improve the urinary dysfunction and the underlying molecular mechanism. After rat model of CP is established by subcutaneously injecting DPT vaccine, rats are treated with resveratrol. Experiments of bladder pressure and volume test in rats are used to investigate the effect of resveratrol on urinary dysfunction in CP rats. To assess tissue fibrosis, picrosirius red staining is performed. H&E staining is performed to identify the histopathological changes. Western blot and immunohistochemical staining are used to examine the expression of c-kit, SCF, tryptase, TGF-β, Wnt and α-SMA. The results of bladder pressure and volume test show that the maximum capacity of the bladder, residual urine volume and maximum voiding are increased significantly in CP rats. CP rats show significantly increased collagen deposition in the detrusor. H&E staining show that detrusor muscle arranged in disorder with fracture from CP rats. The results of western blot and immunohistochemical staining demonstrate that the activity of c-kit/SCF and TGF-β/Wnt/β-catenin pathway, expression levels of tryptase and α-SMA in bladder detrusor of CP group are significantly increased compared with the control group. However, resveratrol treatment significantly improved these factors. mast cell activation induced by the increased expression of c-kit/SCF in CP rats, may promote detrusor fibrosis which have a close relationship with urinary dysfunction. Resveratrol can improve the dysfunction by downregulating the mast cell activation and the activity of TGF-β/Wnt/β-catenin pathway.