The green SiC (silicon carbide) powder, cutting fluid and pure Si (silicon) has the great recovery value in cutting waste mortar of solar silicon wafer. Nowadays, the critical technology of recycling SiC powder is classification technology in which the quality of recovery SiC powder is depended on classification precision. The self developed turbine air classifier (LNC-120A-2 type with two air classifier connected) was used in this experiment. The test dust is dry admixture of waste mortar containing SiC (JIS1200＃) through pretreatment. Through the orthogonal experiment, the optimum classification condition: the speed of first stage classifier is 1914rpm, the speed of second stage classifier is 3480rpm , the secondary air flow of second stage classifier is 13m3/h, the disperse pressure is 0.2MPa and the total system air volume is 1400m3/h. Under this condition, the classification precision of SiC powder is 85.73%, the particle size d50 is 9.571μm meeting the demand of JIS1200＃, the recovery efficiency is 89.2% and yield is 65Kg/h. Sometimes, the results show: the granule morphology of recovery SiC powder is basically some with standard SiC powder of JIS1200＃, meeting the effective cutting for silicon wafer.