Analytic continuation for potential field is a widely used method for processing and interpretation, because downward continuation can suppress the influence of deep geological bodies and protrude the shallow layer anomaly. However, the downward continuation filter factor is a high-pass filter, leading to unstableness of the result, and therefore it can not be used to process the real data. The authors systematically studied and implemented the iterative Tikhonov regularization method for downward continuation of potential fields. In contrast to the continuation of potential field on the theoretical model, the iterative Tikhonov regularization method indicates better effectiveness than frequency domain. The authors also applied this method to Galingeiron deposit's magnetic data processing, and the results indicate that the iteration Tikhonov regularization method for downward continuation of potential fields is worthy to use in heavy overburden exploration areas.