Abstract: In this paper, complete spectral integral representations (Sommerfeld integrals) of the electric-field-type dyadic Green's functions for half-space were derived via spectral-domain expansion of the radiation field of dipole located in free space. The Green's functions of reflection or transmission electric field were given, corresponding to the case of source point and observation point located in the same side or the opposite side, respectively. Especially, the results and physical explains were given for source point and observation point overlapping in vertical direction, which eliminate the singularities arising in the general representations. Numerical computation results show the validity of the presented formulas.