〔Abstract〕 Objective To investigate the distribution of toxoplasma cysts in the brain of infected mice and the effect of pathological changes on the behavior and neuropsychiatry of the mice during chronic infection withToxoplasma gondii(T.gondii). Methods Mice were infected with Prugniaud strain ofT.gondiiby oral gavage. The brain tissues of infected mice were collected on the days of 10, 30, 40, 90, 120 and 160 after infection respectively, and the hippocampal hypothalamus, prefrontal lobe, striatum and cerebellum regions were separated. The number of cysts and neuropathological changes in each infected area were observed and recorded by HE staining. The number of cysts and neuropathological changes in each infected area were observed and recorded. Results T.gondiiinfected mice showed symptoms of vertical hair and arched back, which were the most significant on the 40th day, and then gradually recovered with hemiplegia and circling in circles. At each time point, the number of toxoplasma cysts was the largest in hippocampal hypothalamus, followed by prefrontal lobe and striatum, and the least in cerebellum. The diameter of toxoplasma cysts increased with time. During chronic infection, specific pathological manifestations of toxoplasma encephalitis, such as neuronophagy, were observed in all regions of the brain tissue. The above pathological changes of toxoplasma encephalitis reached the peak on the 40th day, and gradually recovered, and increased to the stimulation peak on the 120th day, and then gradually recovered. Conclusion The behavioral and neuropsychiatric symptoms ofT.gondiiduring chronic infection were correlated with the localization and distribution of toxoplasma cysts in the brain of infected mice, and showed dynamic changes.