The torque of magnetic coupling with different magnetic poles has been investigated by theoretical computations with both FEA and torque formula techniques. The torque of magnetic coupling is sensitive to the number of magnetic poles, and it decreases with increasing the distance between the magnetic rings. From our theoretical computations, we find that we can increase the torque by increasing the number of poles for magnetic coupling between magnetic rings with short distance; however, this is not true for magnetic rings with large separation. We also demonstrate that the theoretical computations of both MagNet software and torque formula established by Furlani are quite consistent and useful for computing the torque of various magnetic couplings. Finally, the theoretical calculation has been successfully tested by using an experimental data taken from a NdFeB magnetic coupling.