The high-frequency method for solving the scattering from the wedges of conductive targets with electrically large size in half space is presented in this paper. To take into account of the influence of environment，the half-space equivalent edge current method is deduced by introducing the half-space Greens function into the equivalent edge current method. Combined with the graphical-electromagnetic computing method，the shadow regions are eliminated quickly and the edge pixel parameters are obtained by reading the edge pixels. Meanwhile，we also make use of the half-space physical optical method to treat the complex targets，and then the radar cross section of the complex targets can be exactly calculated in half space. The numerical results show that this method is efficient and accurate.