Abstract: When 100ppm NaHSO3 was sprayed on to the leaves of peach during the stage of fruit expansion, it coued increase the yield, improve the quality and early ripening. As a result, NaHSO3 could increase the chlorophyll concentration, raise photosynthetic rate and specific leaf weight, promote Hill reaction, inhibit enzyme activaties of hydrogen peroxidase and nitrate reductase, increase fresh weight the fruit.