The invention relates to an energy-controlled DC motor speed regulating device. The speed regulating circuit is composed of a DC motor, a working power supply, a controllable switch, a diode and an excitation power supply. The working power supply is connected to the armature winding of the DC motor through a controllable switch; the diode Connected in parallel at both ends of the armature winding of the DC motor; the excitation power supply is connected to the excitation winding of the DC motor; the control circuit includes a voltage detection circuit, a current detection circuit, an input energy calculation circuit, an inductance energy storage calculation circuit, an electromagnetic torque calculation circuit, and a load Torque calculation circuit, torque coefficient calculation circuit, expected current calculation circuit, energy storage difference calculation circuit, kinetic energy calculation circuit, load energy calculation circuit, output energy calculation circuit, energy comparison circuit, clock circuit, logic drive circuit, speed detection circuit. The invention reduces the volume, weight and cost of the main circuit, improves the operation reliability, and avoids the adverse influence of the defect of the PID controller itself on the performance of the speed regulating device.