Spin polarizer is one of the most important devices for the newly developing field of spintronics,which may revolute the popular information techniques.Here we present a phenomenal model for a novel spin polarizer,which utilizes two back to back ferromagnetic metal/semiconductor Schottky barriers to define a semiconductor transport channel whose length is less than the spin decoherence length of the host semiconductor.Along this channel,conducting electrons move diffusively in momentum space while they keep ballistic motion in spin space.Across the channel,electrons suffer a spin dependent tunneling,which establishes spin polarization along the channel. Spin polarizer is one of the most important devices for the newly developing field of spintronics, which may revolute the popular information techniques. Here we present a phenomenal model for a novel spin polarizer, which enables two back to back ferromagnetic metal / semiconductor Schottky barriers to define a semiconductor transport channel whose length is less than the spin decoherence length of the host semiconductor. Along this channel, conducting electrons move diffusively in momentum space while they keep ballistic motion in spin space. Across the channel, Economics suffer a spin dependent tunneling, which established spin polarization along the channel.