The invention relates to a sand-injecting exhaust pinch valve of a core making machine. The valve comprises a cylinder barrel, a piston and a piston rod, wherein the cylinder barrel is of a hollow structure, an upper cylinder cover is installed at the upper end of the cylinder barrel, an air hole communicating with an interior of the cylinder barrel is formed in the upper end face of the upper cylinder cover, a lower cylinder cover is installed at the lower end of the cylinder barrel, the lower end face of the lower cylinder cover is connected with the core making machine, a through hole communicating with the interior of the cylinder barrel and the core making machine is formed in the middle of the lower cylinder cover, a plurality of exhaust holes communicating with the interior of the cylinder barrel are formed in the outer wall of the lower portion of the cylinder barrel and evenly distributed in the circumferential direction of the cylinder barrel, a silencing barrel is arranged on the outer side of the cylinder barrel in a sleeving mode and is of a hollow structure, the lower end of the silencing barrel is connected with the core making machine through the lower cylinder cover, the piston is sleeved with the cylinder barrel, an inner cavity penetrating through the lower end face of the piston is formed in the piston, the upper end of the piston is connected with one end of the piston rod, and the other end of the piston rod penetrates through the upper cylinder cover and extends out. According to the design, the fault frequency is low, the maintenance cost is low, andthe noise reduction effect is good.