In the present paper, a method of calculating scattering field by a spherical mirror is introduced. Three coordinate surfaces of the spherical coordinate system are used to surround the mirror and separate the space into three regions, in each of which the general solution have been worked out, respectively. Then by making use of the boundary-condition, we obtain a group of equations, by which the coefficients are determined. This equations are used for calculating the radiating field of spherical antennas. The analytic solutions are obtained.