Digital geological mapping three-dimensional model is a new expression of regional geological survey results ( geological maps ). Compared with planar geological maps，it has better readability. In view of the limitations of the current mainstream explicit modeling methods，such as low modeling efficiency，high manual intervention and difficulty in model updating，this paper uses the digital geological mapping data of 1：25,000 Shandang sheet in Jiangxi province to explore digital geological mapping implicit three-dimensional modeling method based on Leapfrog Geo software platform. Fast radial basis function ( FastRBF ) is used to quickly construct geological interfaces such as fault plane，Quaternary bottom interface and stratigraphic interface. According to the new and old relationship of the geological body，these geological interfaces are used to cut and fill the blank three-dimensional volume element model of the modeling area in turn，and the cut three-dimensional volume element model of the geological body is given attributes. The three-dimensional volume element model of all geological bodies is combined to generate the digital geological mapping three-dimensional model of Shandang sheet. At the same time，in view of the difficulty in constructing complex geological models，a block modeling method is proposed. Aiming at the problem that sparse occurrence data cannot directly construct the Quaternary bottom interface，an explicit-implicit interactive modeling method is proposed. This modeling method realizes the high-precision and rapid construction of digital geological mapping three-dimensional model in Shandang sheet，showing a good application prospect.