The invention discloses an output control method for a digital power amplifier based on an NPC inverter, and the method comprises the steps: building a prediction model, and predicting a state variable of a next control period based on a state variable of a current control period; calculating a filter inductor current instruction and a filter capacitor voltage instruction of the next control period based on the input output current instruction of the next control period; establishing an energy function of the digital power amplifier based on the state variable of the next control period and the output instruction of the next control period; taking the energy function as a Lyapunov function, and obtaining a subsystem enabling the derivative of the Lyapunov function to be minimum; and switching the electroacoustic transduction system to the subsystem in the next control period based on the switching action of the subsystem control digital power amplifier. The invention provides an outputcontrol method of an electro-acoustic transduction system, which realizes high-precision tracking of output current on the premise of ensuring the stability of the system, and can effectively reducethe switching loss of a digital power amplifier.