The ef fect of non-biologic environmental factors under satured dissolve oxygen concentration on Penaeus chinensis infected by explosive epidemic virus was studied. The level of salinity, temperature, pH and NH3-N was changed, according to the orthogonal table. Factors appeared different influence degree at the different stages after infection. In 3- 4 days the inf luence degree of these four factors from heavy to light was salinity, pH, temperature and NH3-N, but from the fif th day the order was changed as NH3-N, pH, temperature and salinity. After that, the level of salinity was fixed and the level of temperature, pH and NH3-N was changed , according to mixed level of orthogonal design. The result showed that the inf luence degree of three factors from heavy to light was temperature, NH3-N and pH. This result accorded with the explosive time of the shrimp disease in shrimp culture industry in China. The relationship among environmental factors, and incidence of the disease and mortality rate of Penaeus chinensis was discussed.