In this paper, a novel fast algorithm is presented for electromagnetic (EM) dyadic Green’s functions in horizontal layered medium using direct-waves’ extraction combining with self-adaptive digital filter method. First of all, the direct-waves which characterize effects of homogeneous medium in spectral domain Green’s functions(SDGF) are extracted, and their integrals are obtained by analytical calculations. In this method, the singularity of SDGF is reduced and the integral convergence range is shortened remarkably. Then, we transform the remnant integrals of SDGF into three rapid declining integrals, and self-adaptive digital filter method is introduced to obtain solution quickly. Finally, our numerical results validate the efficiency of the algorithm.