Magnesium silicide (Mg₂Si) is an n-type promising material for thermoelectric (TE) power generation using waste heat with temperature range of 300 to 600°C. Fabricating the multilayer composite of Mg₂Si and metallic material is a useful method for overcoming the weak point in the mechanical property of the material and for making the anisotropic TE material. The transverse TE force is occurred by giving vertical temperature difference in the tilted anisotropic TE material (transverse TE effect). In this study, the Mg₂Si/Ni multilayer composite was focused on for transforming the isotropic Mg₂Si to the anisotropic TE material. The TE properties of the Mg₂Si/Ni tilted multilayer composite were estimated using a finite element simulation. The influences of structural conditions (thickness ratio of Mg₂Si layer and tilt angle) of the tilted multilayer composite on the TE properties were investigated. The TE properties could be related quantitatively with the structural conditions. The structural conditions existed in which the tilted multilayer composite had the power factor greater than Mg₂Si. The optimum structural conditions giving the maximum TE performance were found out.