The invention discloses a constant-
power load control method and circuit applied to a DC-
DC converter, and the method comprises the steps: 1) respectively sampling an output 
voltage and an inductive current through a 
voltage sampling module and a current sampling module, and inputting the sampled 
signal into an ADC module; 2) converting the input sampled 
signal into a 
digital signal through an ADCmodule, and inputting the 
digital signal into a correction module; 3) comparing the 
digital signal with a prediction value obtained by solving a prediction model by using a correction module, and employing the difference value as a correction 
signal to be input into an MLD-MPC control module; and 4) solving the control model by using the MLD-MPC control module according to the correction signal,and achieving the 
constant power load control of the DC-
DC converter according to the calculated switch duty ratio. According to the invention, the problems of steady-state error, poor dynamic performance and the like of a traditional 
constant power control method are solved, so that the DC-
DC converter can quickly and stably adjust and maintain 
constant power output when facing disturbance suchas input 
voltage jump, load jump and the like.