Abstract: An injection molding system includes an injection molding machine, a pressure valve, a flow ratio control valve, a frequency converter, and the flow ratio control valve, a motor controlled by the frequency converter, a hydraulic pump connected to the motor, and an injection molding machine controller for controlling the injection molding machine and the frequency converter. Injection molding conditions and procedures for controlling operation of the pressure valve and the flow ratio control valve are analyzed. The injection molding machine controller sets a maximum output frequency for the frequency converter and a maximum flow for the hydraulic pump, preventing inappropriate operation of a user and avoiding waste of energy. The injection molding machine controller further sets a maximum speed and a minimum speed of the motor and sets a maximum speed and a minimum speed of the hydraulic pump.