Abstract: In order to understand the effect of the input parameters on the estimation results from MACCS model,a station blackout（SBO） accident in a nuclear power plant is taken as an example,and the uncertainty of a severe accident consequence estimated by MACCS model is analyzed using the Latin hypercube sampling techniques.The results of the uncertainty analysis show that:the uncertainty factors of the early individual dose caused by the accident are all about 2.9（95% confidence limited）,and the uncertainty factors of the long-term individual dose are all about 1.7（95% confidence limited）.We can find that:when used to estimate the accident consequence,the MACCS code has an uncertainty within 3（95% confidence limited） caused by the input variables.