Abstract: Based on micro-mechanics Mori-Tanaka method of composite, macroscopic elastic constants of composite predicted by Digimat software and the response coupling relationship between micro-and macro-mechanics for composite was established. Considering manufacturing defects of composite, the method of reverse regression iteration was employed to modify elastic constants of matrix material. Based on the computing platform coupled ABAQUS software with Digimat software, Mori-Tanaka micro-mechanics constitutive model was called in the finite element model of composite leaf spring and micro-mechanics damage of composite was considered, then the numerical simulation of macro-micro multiscale coupling progressive failure was implemented by introducing the fiber and matrix failure criteria which realized ultimate load prediction of composite leaf spring and was validated by ultimate load test of composite leaf spring. The results show that the test fracture location of composite leaf spring consistent with that of simulated prediction, and deviation between test and prediction values of ultimate load was only 5.1%.