Abstract: As a new kind of one-dimension thermoelectric materials, silicon nanowires(SiNWs) have been researched widely in recent years due to its excellent electrical and thermal properties. Theoretically, it is feasible to reduce the lattice thermal conductivity of bulk materials and keep its electrical conductivity as well by embedding SiNWs into the matrix as second phase. In this paper 2at% Bi doped SiNWs-Mg2Si powder was prepared by means of the solution method and consolidated subsequently, and the influence of silicon nanowires on the thermoelectric performance of the Bi-doped Mg2Si matrix was studied. It is indicated that the electrical conductivity of the materials decreased greatly, and the Seebeck coefficient remained roughly the same, and the thermal conductivity reduced a small amount. With the increase of the dosage of SiNWs, the electrical conductivity furtherly decreased, and the Seebeck coefficient slightly improved, and the thermal conductivity had a rising trend. The sample with 0.1at% SiNWs embedded obtained a highest ZT value of 0.5 at 800K.