Aimed at the problem existed for extending service life of aircraft structure at present, a method of fatigue /durability safe life extension of aircraft structure is put forward, i.e. the equivalent service life extension method. The basic principle of equivalent service life extension method can be illuminated as: the test data and service data of the same type of fleet aircraft are transferred into the equivalent using data under the same loading spectrum, the equivalent using data are fused and comprehensively analyzed based on reliability theory, then the fatigue /durability safe life of fleet aircraft are assessed and extended (namely the service restriction of fatigue safe life is relaxed). The basic process of equivalent service life extension method is described further on the basis. According to the basic principle and process of equivalent service life extension method, the fatigue /durability safe life of fleet aircraft structures can be determined and extended, the service restriction of the same type of serve fleet aircraft is relaxed gradually. The equivalent service life extension method can be used to provide the theoretical basis for the service life extension of the same type of service fleet aircraft.