The invention provides a conductive gold-coated polyimide fiber and a preparation method thereof. The conductive gold-coated polyimide fiber comprises a modified polyimide fiber as well as a palladiumparticle layer and a gold layer which are composited on the surface of the modified polyimide fiber in sequence; the modified polyimide fiber is a polyimide fiber containing carboxylate on the surface or a polyimide fiber which is bonded by ester linkage and contains a pyridine derivative or a quinoline derivative on the surface. The fiber adopts the polyimide fiber as a base fiber and is modified with carboxylate or the pyridine derivative or quinoline derivative bonded by the ester linkage, so that the thermal shock resistance of the gold-coated fiber is improved. The conductive gold-coatedpolyimide fiber is higher in electric conductivity and has excellent corrosion resistance and oxidation resistance and wide using temperature range. The fiber has good thermal shock resistance at subzero 180 DEG C-200 DEG C, and avoids metal falling after 10 times of cycle; the electric conductivity is 4.53*10<3>-1.87*10<4> S/cm; electric conductivity and mechanical property of the fiber in the corrosive environment and oxidizing environment can be maintained.