The invention relates to a preparation method of ginger peel dietary fibers and solves the technical problem of non high-value utilization of existing ginger peels. The method comprises the following steps: pulping, grinding by a colloid grinder, performing microwave treatment, performing ultrasonic-assisted a-amylase and glucoamylase treatment, performing ultrasonic-assisted neutral protease treatment and microwave enzyme deactivation, performing ultrasonic-assisted cellulase treatment and microwave enzyme deactivation, performing ultrasonic treatment, performing alcohol precipitation, centrifuging, drying, and sieving. The method is widely used for preparing the ginger peel dietary fibers.