The invention provides a lifting device for a valve spring. The lifting device for the valve spring is characterized in that the lifting device comprises a motor and a piston; the motor includes an electromagnetic coil, a rotor and a turning wheel; furthermore, the turning wheel is designed to be of an inner hollow structure and is designed into threaded teeth encircling around an inner circle through the hollow structure; and a push rod of the piston is screwed into the turning wheel, and the turning wheel is fixed to the rotor. When the rotating speed of an engine is high, the pressure of the valve spring is large; and when the rotating speed of the engine is low, the pressure of the valve spring is small. The pressure of the valve spring is increased at the high rotating speed of the engine, and the pressure of the valve spring is decreased at the low rotating speed of the engine.