The present invention relates to an overcurrent protection method and a grid structure applicable to a power distribution network with distributed generations (DGs). Circuit breakers are arranged at both sides of each busbar on each feeder line. The feeder line with the DGs is segmented according to the number of the DGs, and circuit breakers are arranged at both sides of each DG access point. All protection positions are equipped with power directional elements and non-channel protection criteria. According to double-end power supply distribution network graded time setting principles, delayed time setting is performed on the protection positions. Protection at two sides of each segment of circuit is set according to different sets of graded time, i.e., protection at one side is set according to a direction from large to small while the other side is set according to a direction from small to large. Constant time-lag directional overcurrent protection and non-channel acceleration protection are combined and applied to relay protection of the power distribution network with the DGs, rapid positioning and isolating of faults are completed, trip acceleration of the whole circuit is realized, and the above technical scheme is a scheme which takes both economical efficiency and reliability into account.