Abstract: Effects of constant temperature heating with microwave on the quality of peanuts were studied. In order to probe the advantage and applications of microwave heating with constant temperature control, peanuts was taken as testing material to compare the difference of drying quality with conventional gradient microwave heating and microwave heating with constant temperature. Results showed that the drying quality of peanuts by microwave heating with constant temperature was much better than that of drying by conventional gradient microwave, the later would easily cause burned products and skin leveling off. The results proved that the microwave heating with constant temperature could ensure the maximum quality of dried peanuts when the microwave power was 1.20 W/g and the temperature was between 45-50℃.