The invention provides a delay-based heuristic peak load reduction method, which comprises the steps as follows: a regulation center gives a peak load reduction instruction to a load agency; the load agency obtains power amplitudes, duty ratios and periods of periodic flexible loads within a management region, builds a load model and a peak load reduction model according to parameters of the load, calculates a starting time delay of each periodic flexible load and gives a control signal to electric equipment; and the electric equipment regulates the starting time according to time delay parameters after receiving the load control signal. A small phase delay is exerted in a work period of the intelligent electric equipment, so that reduction of overlapping of periodic loads and minimization of the maximum overlapping value of periodic pulse waves are achieved to achieve peak load reduction.