Southeastern Zhejiang is an important component part of the Southeast China volcanic belt. Late Jurassic volcanic rocks are widespread, and their thickness is 1～2 km and locally even reaches over 3 kilometers, suggesting that volcanic activities were very frequent in that period. There exist various mineral deposits related to volcanic hydrothermal fluids in this area, and hence the delineation of volcanic structures constitutes an important means for discovering various kinds of ore resources. With Zhilingtou area as an example, this paper indicates the role of 1:50 000 gravity survey in Ⅳ and Ⅴ grade volcanic structure delineation, probes into the relationship between volcanic structures and mineral deposits in this area, and then points out the most favorable places in the ore prospecting work of this area.