Abstract: The study of the edge location of the geological body is the most important task in the processing and interpretation of gravity and magnetic potential field data. The results of relevant map can show the geological body's edge location directly by means of filtering processing with the gravity and magnetic potential field data. Small subdomain filtering is one of the filtering methods, and it has been used by many researchers to recognize the edge location of the geological body. There are 10 kinds of small subdomain filtering methods at present; however, rare studies have analyzed the filtering effect about those methods systematically, and this brings much inconvenience to users. Therefore, the authors designed 2 theoretical models to compare their filtering results and then selected the optimal filtering parameters. The results of theoretical model and field data show that the moving shape small subdomain filtering method has the best effect on enhancing the edge location of the geological body, and the filtering window chooses 5×5 points and 1 iteration. The symmetrical shape small subdomain filtering method can preserve the main gradient direction when filtering the random noise, and the filtering window chooses 5×5 points and 2 iterations.