In the traditional matrix analysis of the criticality of aviation products,hazard degree calculation has low accuracy and efficiency.To solve the problem,a criticality assessment method based on a planar cloud model is proposed.Firstly,the planar cloud model is used to analyze the criticality of a single failure mode and solve the criticality level of a single failure mode.Then,gray relation and clustering analysis as well as information entropy are used for weighting the failure modes.The criticality levels of various failure modes are clustered as the criticality level of the whole product.Finally,the correctness of the proposed method is verified by a case analysis of the elevator control subsystem of a certain aircraft.