On the basis of pointing out the background and significance of distributed generation, this paper establishes a constant power equivalent model of distributed generation (DG). This paper analysis the specific effects to original current protection from a theoretical point of view when the distributed generation is at different location of the fault. In PSCAD simulation software, this paper builds a typical model of 10kV distribution network with DG and uses full-wave Fourier algorithm to calculate the magnitude of the short circuit current fundamental current amplitude, which show the theoretical analysis is correct compared with the protection setting values. This paper proposes the adaptive current protection scheme based on local information, which can provide a certain theoretical basis for relay protection algorithm with DG.