CuBe/insulator/NiCoP composite wire was produced by electroless-deposition and annealed using Joule annealing method with a dc current of 2 A for 2 min, in which the influence of current annealing on giant magneto-impedance (GMI) effect was investigated. The results showed that the GMI effect in the composite wire can be greatly enhanced by dc Joule annealing. The GMI ratio increases from 42.3% of as-deposited sample to 693.1%, about 15.4 times. The property of magnetization and the enhancement mechanism of GMI effect were analyzed in terms of complex permeability and equivalent circuit. Because the dc Joule annealing can release the internal stress and change the magnetic structure of specimen,Δμ′ and Δμ″of annealed composite wire is much greater than that of as-deposited, resulting in the enhancement of GMI effect.