The invention provides a mould clamping system for an injection molding machine and belongs to the technical field of hydraulic transmission; the problem that an existing mould clamping system used for the injection molding machine has a poor mould clamping effect is solved by the mould clamping system for the injection molding machine provided by the invention. The mould clamping system for the injection molding machine comprises an oil tank, a first oil way, a second oil way, mould clamping oil cylinders and cutoff units, wherein the oil tank is used for storing oil; the first oil way communicates with the oil tank and is used for delivering the oil; the second oil way communicates with the oil tank and is used for delivering the oil; the number of the mould clamping oil cylinders is multiple, and each mould clamping oil cylinder communicates with the first oil way; the cutoff units and the mould clamping oil cylinders are in one-to-one correspondence; the cutoff units communicate with the second oil way and are used for driving the corresponding mould clamping oil cylinders to perform mould clamping. The mould clamping system disclosed by the invention has the advantages that a mould clamping force can be adjusted independently, and the mould clamping effect is good.