Because of the lack of scale calibration on the analysis results of information system business impact analysis as well as the influence of expert evaluation preference on it, an analysis method of system business affecting impact based on crossover probability theory is proposed. First, the experts evaluate the relevance and influence of the business functions of the information system, and the correlation between business functions is represented by a cross-impact matrix. Then, the subjective and objective weight combination method is used to weight the matrix to re? duce the subjective impact of experts scoring on the cross-impact matrix, quantify the correlation between system business functions, and generate a comprehensive cross- impact matrix. Finally, the preference chain generation algo? rithm is used to generate the business preference chain of the information system, and the interaction relationship of each business of the system is associated. On this basis, the influence trend of other businesses after the business in? terruption is obtained by analyzing the position of the interrupted business in the preference chain. Experimental re? sults show that the proposed method can accurately measure the impact and trend of business function interruption on other business functions of information system.