The invention relates to a method for uniformly 
drying agaricus bisporus slices through variable-frequency 
ultrasound-assisted impregnation pretreatment and vacuum microwaves, and belongs to the field of 
deep processing of agricultural products. The method comprises the following steps: cleaning 
agaricus bisporus and 
cutting into 5-8mm thick slices, protecting color by using a 
mixed solution of 
vitamin C, 
citric acid and 
calcium chloride, and carrying out variable-frequency staged 
ultrasound impregnation treatment on the color-protected 
agaricus bisporus slices: a first stage: putting the 
agaricus bisporus slices in clear water according to a ratio of 
agaricus bisporus slice to water of 1:5, and setting the 
water temperature to 45-50 DEG C, the ultrasonic frequency to 45KHz, the ultrasonic power to 120-150W, and the 
treatment time to 30-40min; a second stage: taking out the 
agaricus bisporus slices and putting into a 
mixed solution of 50-60% by 
mass fraction of 
sucrose and 5% by 
mass fraction of salt according to a ratio of agaricus bisporus slice to 
mixed solution of 1:10, and setting the 
water temperature to 35-40 DEG C, the ultrasonic frequency to 100KHz, the ultrasonic power to 210-240W and the 
treatment time to 40-50min; finally, carrying out vacuum 
microwave drying, and setting the 
microwave transmitting power to 15-20W / g, the degree of vacuum to 70-80kPa and the 
drying time to 15-25min. The agaricus bisporus slices subjected to variable-frequency 
ultrasound-assisted impregnation treatment has uniformly distributed dielectrics; when the vacuum 
microwave drying is carried out, a material is uniformly heated in a microwave field, and 
moisture is rapidly evaporated, so that the dried agaricus bisporus slice is uniformly distributed in color and luster, and is uniform in shape and better in rehydration.