The electromagnetic interaction between spherical targets is researched. The second scattering field for a target is derived in detail. The complex scattering field and the bistatic radar cross section are presented respectively. The simulation results in Ku wave band show that the size of the principal target affects greatly both the forward and the backward scattering. The influence of the surrounding targets shows definite periodicity. The secondary scattering field diminishes with the increase of distance between the two targets. The nearer to the forward area the surrounding target is, the bigger its affect. The magnitude of the secondary scattering field is about 10-4 that of the first scattering field. The size of surrounding particles can be considered as stable and uniform when researching the electromagnetic interaction. This kind of interaction in three dimensions can be investigated easily by using the obtained result and coordinate transformation.