A blade clamping centering adjusting device of an indexable insert periphery grinding machine is characterized by comprising a V-shaped locating block, a vertical moving block, a horizontal moving block, a guide fixed block, a flange base, a horizontal differential screw, a vertical differential screw, a wedge block A, a wedge block B, a guide post and a compression spring. The V-shaped locating block is installed on the vertical moving block, the horizontal moving block is connected with the flange base through a dovetail groove in the horizontal moving block and the wedge block B, the guide fixed block is connected with the flange base through a dovetail groove in the guide fixed block and the wedge block A, the vertical differential screw is connected with the vertical moving block and the horizontal moving block, and the horizontal differential screw is connected with the guide fixed block and the horizontal moving block. The blade clamping centering adjusting device is simple in structure, small in size and low in manufacturing cost, does not rely on operation workers' experience level in use, does not need to be by means of other auxiliary tools, is high in efficiency and centering precision, greatly shortens processing auxiliary time and improves processing efficiency and precision of an indexable insert.