The invention discloses a method for evaluating damage and fatigue life of a microscopic-macroscopic scale sheet metal forming process model. According to the method of the invention, a microscopic plastic constitutive model is established and macro geometry is coupled; furthermore sheet metal forming process simulation is performed; based on sheet metal forming process simulation, a microscopic-macroscopic coupling fatigue damage model is established for performing fatigue life simulation; a sheet metal forming process and a fatigue failure mechanism are researched, thereby supplying theoretical guidance and technology optimization basis for engineering application. Sheet metal forming process material performance and plastic deformation evolution distribution are researched in a microscopic aspect. Influence and contribution degree of microscopic characteristics such as crystal grain size and orientation distribution and precipitated phase distribution to the sheet metal forming process are researched. Furthermore the macroscopic model and process researching fatigue damage are coupled, and the component fatigue life is evaluated. The invention provides the reliable high-efficiency calculating model and the evaluating method. Establishment of the related model and the algorithm has important science innovation and high engineering application value.