Abstract: Based on a novel micromechanics modeling method-variational asymptotic homogenization theory, a micromechanics model for magnetostrictive composites was established to accurately predict the effective material properties and local distribution of stress and magnetic flux density. Starting from the total magnetic enthalpy of the magnetostrictive composites, the exact solutions of field variables in the magnetic enthalpy were expressed as the sum of mean values and the fluctuation function. According to the principle of minimum potential energy, the micromechanics model was formulated as a constrained stationary problem by taking advantage of the small parameters of the ratio of microscopic scale to macroscopic scale. To handle the microstructures in realistic engineering applications, the new model using the finite element discretization technique was implemented. The numerical example of CoFe₂O₄/epoxy composites show that the model can accurately predict the effective properties and the local field distribution of magnetostrictive composites, and can be extended to the effective properties and local field analysis of other multiphase composites.