The invention provides a double fed wind driven generator rotor transient current calculating method. The method includes the following steps that: a transient mathematical model of a double fed induction generator in power grid voltage abrupt rise is established in a synchronous speed rotation coordinate system; a stator and rotor transient current equation in power grid voltage abrupt rise is calculated according to the transient mathematical model; a stator flux linkage, a stator flux linkage equation in rotor open circuiting and the equation of a rotor flux linkage inducted from a stator side are calculated for a set voltage abrupt rise switching-in mechanism; and an expression of rotor transient current which is generated through induction due to the abrupt change of the electric quantity at the stator side after power grid voltage symmetrical abrupt rise is obtained according to the stator and rotor transient current equation in power grid voltage abrupt rise, the stator flux linkage, the stator flux linkage equation in rotor open circuiting and the equation of the rotor flux linkage inducted from the stator side. The method of the invention has the advantages of simple calculation process and accurate result, and can provide a reliable data base for the setting work of the power protection system of the double fed induction generator.