Cooling-air grinding is one of important green grinding technology. Cooling-air grinding performances for 40Cr are tested in this paper using cooling-air generator. Main performance influencing factors are tested and analyzed, such as air temperature, wheel granularity, amount of feed and so on. Cooling-air grinding results showed that roughness of surface of specimen can reach to precise grinding standard. So cooling-air grinding can replace traditional grinding in this experiment. This study for the promotion of cooling-air grinding application technology has important significance for reference.