Aiming at the problem of insufficient application of risk matrix, Bayesian network, and probabilistic risk analysis in actual risk assessment, proposes a comprehensive fuzzy cognitive map method and fuzzy evidence cognitive map method of evidence theory advantages. The risk assessment framework of complex equipment maintenance is given, and the principle of maintenance risk assessment based on fuzzy evidence cognition map is expounded. Taking a diesel engine maintenance project as an example, the risk analysis and risk consequence level are used to analyze the risk and obtain specific control measures. The results show that the method is feasible and effective.