With a certain depression of Bohai bay basin as an example, this paper deals with the application effect of such new techniques as the second-vertical derivative after downward continuation to a given depth, the 3D apparent density inversion, and the joint modeling and inversion with gravity, magnetic and seismic data in LCT platform. The anomaly of second-vertical derivative after downward continuation to a certain depth can reflect small-scale, low amplitude and deep-seated buried hills more effectively and intuitively compared with the conventional second-vertical derivative anomaly. The 3D apparent density inversion section can reflect the density variation of the geological body both vertically and horizontally and provide evidence for buried hill research. The application of LCT joint inversion with gravity, magnetic and seismic data can quantitatively determine the depth and amplitude of buried hills.