Objective   					To study the relationship between oxidizing damage and pathogeny of mice with Pneumocystis carinii pneumonia(PCP).
					   Methods   					The pathology, infecting protozoa numbers and the challges of measuring value of GSH, MDA, XOD of Lung, brain tissue and serum of infected mice were observed.
					   Results   					The film appeared a large number of protozoon, there were congestion and inflammation on alveolus wall.MDA and XOD rose and GSH dropped in lung and brain tissues of infected mice.
					   Conclusion   					Except inflammation damage leaded by protozoa itsef, the pathogeny of PCP relates to oxidizing damages by oxygen free radicals.