The invention discloses a method for realizing digital control of multi-phase alternating on-state current for laser load. Whether the input pulse of a multi-phase alternating on-state circuit is in ajumping stage is judged, a variable-gain feed-forward parameter is added to a feed-forward controller in the stage, and the output current sampling signal, the inductive current signal and the pulseinput current reference signal of a main power circuit are calculated by using a DSP controller. The difference signal between the output current sampling signal and the pulse input current referencesignal is calculated, and the error coefficient ratio is calculated and compared with a feed-forward start threshold. If the condition is satisfied, threshold interval division is carried out on the error coefficient ratio, and matching feed-forward variable-gain parameters are found for the threshold intervals and input to the feed-forward controller. The judgment on whether a laser load module uses a variable-gain feed-forward control mode is realized by an online algorithm, and the adjustment of the transient current rise rate of the laser load and the optimization of the system performanceare realized.