Objective To establish an animal model of chronic nonbacterial prostatitis induced by chemical substances, and provide a reliable animal model and evaluation method for pathological mechanism and pharmaceutical research of chronic nonbacterial prostatitis. Methods SD male rats were randomly divided into control group and model groups A, B and C. The three model groups were respectively treated with 20, 50 and 100 μL of 1% sterile carrageenan, injected into the left and right ventral lobes of rat prostate. The control group was injected 50 μL sterile normal saline. The rats were sacrificed at 7 days after carrageenan injection, and the anatomical changes were analyzed, and the prostate index, leukocyte count, the histology of prostate, and the protein expressions of TNF-α, NF-κB, IKKα, p-IKB-α and COX-2 were analyzed.Results Compared with the sham operation group, the softness of prostate tissue of groups A, B and C was decreased, the elasticity of the prostatic tissue was weakened, and the prostate tissues of model groups were adhered to surrounding tissues. The total number of leukocytes and the prostate index of model groups A, B and C were significantly increased (P<0.01), by 21.1%, 61.7% and 72.7%, respectively. The total increase rate of white blood cell in the model groups A, B and C was 75%, 103.6% and 114.8%, respectively. Pathological examination showed that the interstitial edema of the prostate of model group A was minimal, but obvious in the groups B and C. Moreover, in the group C, the prostate atrophy was obvious, and some of the glands were degenerated and necrotic. The protein expression levels of NF-κB, IKKα, p-IKB-α, TNF-α, and COX-2 in the prostate tissue were increased to a different extent in all model groups.Conclusions Inflammatory reactions can be induced by injecting 20, 50 or 100 μL of 1% sterile carrageenan into the right and left ventral lobes of the rat prostate. However, the 20 μL dose is too small, inducing only weak inflammatory response, with considerable operation error, while the dose of 100 μL induced excessive inflammatory response, even rat death. The dose of of 50 μL injection is most suitable to establish rat models of nonbacterial prostatitis, showing apparent activation of NF-κB inflammatory signaling pathway.