Abstract: The method for building k-voronoi diagram is discussed and the k-voronoi diagram characters is mined and argued.Referring k-data field's definition from k-voronoi diagram's definition,low k-data field's approximation common function is proposed combinated with reference points and its factors function.The plane space most-close-units division is realized and thus the integrity data field can approximate individually through low k-data field's surface approximation group by each units,which way can greatly dissolve the difficulty of building large number points' surface approximation.In order to integrate these small units' data field,combination integration policy and superposition integration policy are put forward to keep the final data field integrity and smoothly.As a good example to testify the legitimacy of proposed method,the potential function replaces the factor function and the radiant points data field's approximation is realized.