Abstract: Before the successful development of this system, the coil spacing in the magnetic field coil system was fixed and there are large magnetic gradients in almost all the environment; therefore, the uniformity and orthogonality designed theoretically were not adjustable or able to be supervised or corrected when the environment changed. The development of this system makes the coil spacing relatively equally adjustable or asymmetrically adjustable and so can compensate the magnetic gradient in the objectivc environment,thus raising the precision of supervision, solving the problem of the magnetic gradient correction effectively and filling in the gap in this application in China.