A widely used way to realize LVRT is adding a crowbar circuit to the DFIG, however, the choice of crowbar resistance is difficult and it has a key influence on LVRT during the grid faults. In recent years, there have been many studies on the choice of crowbar resistance, however, these studies generally give a broad resistance choice scope, and the designer can only choose the crowbar resistance by trial and error method to get a better LVRT process, hence, the efficiency is not high. In this paper, a crowbar resistance design method based on fuzzy membership function is proposed, it can improve the design efficiency of crowbar circuit greatly and achieve a higher degree of satisfaction during LVRT process. This paper analyzes the change process of stator and rotor fault current, obtains the constraints relation of crowbar resistance with rotor side current and DC-link voltage, then transforms the crowbar resistance constraint equations into the fuzzy membership function, and finally establishes a DFIG model with Crowbar circuit on the Matlab simulation software platform. The simulation results which verify this crowbar resistance design method can get the satisfy result on the maximum balance and improve the efficiency of selection of the crowbar resistance greatly.