The invention discloses an injection molding machine, comprising a servo-controlled system, wherein the servo-controlled system comprises a control valve, an oil tank, an oil outlet pipe, an oil return pipe, a fixed displacement pump and a hydraulic cylinder as the power of the injection molding machine, the oil outlet pipe and the oil return pipe are connected with the control valve and the oil tank and are arranged between the control valve and the oil tank, front and rear cavities separated by a piston are arranged in the hydraulic cylinder, the two cavities are respectively connected with the control valve, the fixed displacement pump is arranged on the oil outlet pipe, the servo-controlled system further comprises a servo motor, a rotary encoder, a servo drive controller and a pressure sensor, the servo motor is connected with the fixed displacement pump in a transmission way; the rotary encoder is arranged on the servo motor, and the output signals are input to the servo drive controller; the pressure sensor is arranged on the oil outlet pipe, and the output signals are input to the servo drive controller, and the servo drive controller is electrically connected with the servo motor. The injection molding machine has the following advantages: 1, good energy-saving performance; 2, quick respond speed; 3, high repeat precision; and 4, prolonged service life of the hydraulic system.