A kind of spintronics is designed by doping the transition metal into Si clusters. Their spin-polarized electron transport properties are investigated by using the first principle analysis. Calculation shows that Fe, Cr and Mn atom doped clusters give the largest spin-polarized transmission coefficients in all the clusters. From Sc to Ni doped clusters, spin filter efficiencies of the systems increase gradually, and the maximal spin filter coefficiency appears in the Fe doped system. The ability to induce the spin-polarized electron transport of the cluster in junction is not cosistent with the magnetic moment of cluster under isolated states.