The invention discloses a switching control method based on a discrete Lyapunov function, and belongs to the field of power electronic conversion technique and intelligent control. The method comprises: according to a discrete mathematical model of a converter, defining a discrete Lyapunov function based on an error term of a controlled variable and a reference variable, obtaining a control law by a Lyapunov stability second theorem, selecting different defined variables [alpha] in a dynamic response phase and a steady state phase, then through PWM, outputting a switching signal. The method comprises a feedback term of the controlled variable, an error value compensation term of the controlled variable and the reference variable, and a feedforward compensation term input by future reference. The control method is simple in principle and easy in digital realization, and is combined with advantages of no-beat control and characteristics of feedforward-feedback of model prediction control, and has advantages of fast dynamic response, good control performance, and good robustness.