Abstract: Operating platform inside the containment is one of the important contents of nuclear power plant fire risk assessment. In this paper, the risk analysis of fire between Operating platform inside the containment in typical NPPs is carried out. Based on the deductive analysis of the fire sequence of the containment platform in nuclear power plant, the probabilistic safety analysis model of the containment platform fire is established and evaluated quantitatively. The influence of three fire scenarios on the initial event and system equipment of nuclear power plant is analyzed. Risk quantification results show that the frequency of core damage caused by fires between Operating platform inside the containment is 3.11×10^-8/（reactor·year）.