An ECMS-based PHEV four-drive torque distribution method is disclosed. The method comprises: step 1, calculating an equivalent fuel consumption factor; step 2, calculating instantaneous total equivalent fuel consumption rate; step 3, converting all operating torque combinations of an engine, a BSG motor and a rear axle motor into the operating torque of a driving wheel, and determining the operating torque range of each power source; step 4, solving the minimum value of the instantaneous total equivalent fuel consumption rate within the actual operating torque range of each power source; and step 5, taking the operating torque of each power source corresponding to the minimum instantaneous total equivalent fuel consumption rate as the PHEV optimal operating torque for distribution.