In order to evaluate the operation status of the gearbox scientifically and rationally,an evaluation model of operating status based on the game theory combination was proposed.Firstly,a gearbox operating state evaluation index system was established based on the main monitoring indicators of the lubricating oil.Then the improved AHP method and entropy method were used to give subjective and objective weights to the evaluation indicators,and the game theory idea was used to obtain the optimal comprehensive weight.Finally,a fuzzy comprehensive evaluation model of the gearbox operating state was constructed.This model was used to evaluate the running state of the gearbox of an armored vehicle chassis system.The results show that the calculation method of the model is simple,the comprehensive weight obtained is accurate,and the evaluation result is generally consistent with the operating status,which can provide a theoretical basis for condition-based maintenance.