The approximate expressions of special solutions of the paraxial equation and its paraxial lateral aberrations have been explored by an ideal model of a combined electromagnetic concentric spherical system in this paper. The approximate expressions of two special solutions of the paraxial equation in a combined electromagnetic concentric spherical system have been derived, and on this basis, some special types of paraxial lateral aberrations such as paraxial spherical-chromatic aberration, paraxial magnification chromatic aberration, and paraxial anisotropic chromatic aberration have been deduced. The results show that the paraxial lateral aberration deduced from the approximation of two special solutions is exactly the same as through the exact solution, which proves the feasibility of the approximation to solve the paraxial lateral aberration.