The technique for improving the evaluation of equivalent source by meansof resolving singular values of ill-conditioned system of equations is discussed inthis paper, and on such a basis, reduced to the pole is tentatively performedunder the condition of varying magnetic directions and small magnetic dips,which has been formerly considered to be extremely difficult. Moreo ver, it makesa further approach to the possible solution of the problem of gravity andmagnetic inversion by equivalent source method. The theoretical model andcalculations for ore’ districts all demonstrate the correctness of this technique.