The invention relates to an adjustable sizing block. At present, an adjustable sizing block capable of being used in overloading environments and environments requiring frequent adjustments is not provided. The adjustable sizing block is characterized by comprising a base, a slide block, an adjusting screw rod, a fastening nut and a lifting wedge block, wherein a slide block sliding cavity, an adjusting screw rod hole, a base through hole and a horizontal limiting port are formed in the base; the top surface of the slide block is an upper inclined plane of the slide block, and a slide block through hole and an adjusting screw hole are formed on the top surface of the slide block; the slide block is positioned in the slide block sliding cavity; the slide block through hole is positioned right above the base through hole; the adjusting screw rod is penetrated into the adjusting screw rod hole, and is connected with the adjusting screw hole through threads; the fastening nut is connected to the adjusting screw rod through threads; the bottom surface of the lifting wedge block is a lower inclined plane of the wedge block, the top surface of the lifting wedge block is an upper plane of the wedge block, and a wedge block through hole is formed on the top surface of the lifting wedge block; the lifting wedge block is arranged on the slide block; the wedge block through hole is positioned right above the slide block through hole; and the lifting wedge block is positioned in the horizontal limiting port. The adjustable sizing block is easy to operate, and is applicable in the overloading environments and the environments requiring frequent adjustments.