Implicit surface reconstruction has been a challenging work for decades. In this paper, motivated by the concept of classic physical polar field model and off-set points strategy, we present a new approach, called Field Fitting. In this approach, we express a 3D surface as an equipotential surface of scalar polar field which is produced by a number of paired field generating primitives, then a surface reconstruction process is cast as a primitives localization process, and finally, we solve this problem with a greedy method. Experimental results demonstrate that the proposed method outperforms the previous by providing better surface reconstruction results. Key words: surface fitting, reconstruction, polar field, implicit surface, Field Fitting