Operational consequence analysis of system failure is an important branch of aircraft operational reliability analysis, which can provide strong support for cost-benefit analysis of maintenance tasks. In order to study the impact of aircraft system failure on operational consequences and costs, this study starts with the correlation analysis of operational consequences of system failures. Firstly, the impact of aircraft system fault types and release conditions on operational consequences is analyzed. Then, combined with the current practice of airline maintenance and the idea of event tree, a method to support the evaluation of operational consequences and related costs of aircraft system failures is proposed, and the operational consequence and cost assessment model based on aircraft system failure is established. Finally, the feasibility and applicability of the proposed method are verified by taking the fuel system of a certain type of aircraft as an example. The results show that the proposed method is reasonable and effective, which can provide support for evaluating the consequences of failure operation, and provide certain reference for aircraft design, operation and maintenance.