To overcome the difficulty in the design of such top indexes as Reliability, Maintainability, Supportability and Testability (RMST) in the development process of complex modern equipment, an integrated RMST design method based on efficiency is proposed.Firstly, the meaning of RMST index and the definition of equipment efficiency are analyzed, the main factors affecting equipment efficiency are selected, and the object of trade-off optimization in the integrated RMST design is clarified.Secondly, according to the relationship between the selected RMST index and equipment efficiency, the comprehensive expression of equipment efficiency model and the cost model of equipment development are established respectively.Finally, taking the cost of equipment development as the constraint and the maximization of equipment efficiency as the decision object, a trade-off optimization model of the integrated RMST design is established.The example analysis shows that the trade-off optimization model is effective and can provide a reference for determining RMST index in the development process of complex modern equipment.