Abstract: The accident analysis model of AP1000 was established by using integrated safety analysis code. On the basis of analyzing progression of accident, the characteristics including fission products release and transport were analyzed and computed. The distributions of inert gases, volatile fission products and nonvolatile fission products were focused. The sensitivity impact of break location, break size and leak rate of containment was also analyzed. The analyzed results of this paper may give some support for severe accident management and assessment of the accident consequences.