Abstract: Guide vane is the important part in the classification zone of classifier，a L-shape guide vane with groove facing the rotor is designed，and the classification zone composed of guide vanes and rotor is taken as the air-solid two-phase turbulent theoretical model. Reynolds Stress Model (RSM) and Eulerian- Lagrangian Particle Trace Model are used to do numerical simulation. The results show that the L-shape guide vane can achieve rapid classification，and reduce particle agglomeration. Influenced by greater centrifugal force，coarse particles are thrown to the lee side of the guide vane and lose their momentum，then drop to the grit funnel rapidly by gravity force，greatly avoiding particle back mixing generally observed in traditional flat guide vane，and reducing the interference of the following particles by coarse particles already classified，thus assuring the stabilization of classification process. According to numerical simulation and experience，the installing radial obliquity of L-shape guide vane of 55º is appropriate. The experiment results indicate that L-shape guide vane is helpful to improving classification precision and efficiency.