The invention relates to a special grinding machine for the ground finish of a crystal silicon square billet, comprising a base on which a guide rail and a worktable are arranged, a first lateral grinding power head, a second lateral grinding power head, a first chamfering mechanism, a second chamfering mechanism, a carrying mechanical hand and an overturning platform. The invention has the advantages that multiple times of clamping are dispensed with, the production efficiency and the machining accuracy are high, and the defective rate is low.