Herbal prostatitis decoction is a great effective prescription to treat chronic prostatitis in promoting the blood circulation and relieving the stasis. The authors had succeeded in making rats experimental fibrous proliferation type prostatitis models by using xiaozhiling injection method. Rats were divided into two groups: the decoction-given group (DG) and the water-given group (WG). Microscopically, both inflammatory cell infiltration and fibroblast proliferation of interstitial tissue in the DG were slight than the WG (P less than 0.025, P less than 0.05). Transmission electron microscopic observations showed both the secretary particles and metal-granule-like substances (including Zn) of the gland cells in the DG were obviously increased. The lysosomes in the cytoplasm were increased also. The results performed a certain experimental basis for the functional mechanism of the herbal prostatitis decoction treatment.