For predicting the milling force in process of micromilling aluminum alloy,the law for micromilling force changing under different milling parameters was studied.The elastic-plastic finite elelent model of micromilling was found using general commercial software.During modeling,the Johnson-Cooks coupled thermalmechanical model Was used as workpiece material model,the Johnson-Cooks shear failure principle Was adopted as workpiece failure principle,and the coupled thermal-mechanical hexahedron strain hybrid modules and self-adaptive grid technology based on the updated Lagrange formulation were used to mesh the workpieces elements,while the friction between tool and workpiece obeys the modified Coulombs law that combines with the sliding friction and the adhesive friction.By means of finite element analysis,the law for micromilling force changing under different milling parameters Was obtained,and the results were analyzed and compared.Finally micromilling experiments were carried out to validate the results of simulation.