The invention discloses a control method of low voltage ride through of a wind driven generator set based on a DGNR variable pitch system. Before the grid voltage declines, a main control system operates in a normal generation state; when the grid voltage declines, a LVRT (low voltage ride through) starting signal is detected by a converter; the main control system is triggered to enter the low voltage ride through state from the normal generation state according to the LVRT starting signal by the main control system triggers; faults relevant to the grid are shielded by adopting a manner of a filter; the converter and the variable pitch system are triggered to enter the low voltage ride through state; the variable pitch system feathers one time by the variable pitch battery energy till that the measured blade pitch angle of the variable pitch system is more than the set blade pitch angle of the variable pitch system; the blade brake and the variable pitch motor electromagnetic brake are controlled by the variable pitch system to perform braking; and the blade pitch angle is temporarily and firmly held to wait for the grid voltage recovery. The method is low in cost, good in applicability and strong in practicability.