Abstract: The precision of gravity and magnetic data interpretation depends, to a great extent, on the validity of physical properties and the rationality of structure-s geometric shape. In the area with limited rock samples, gravity-magnetic-seismic multi-parameter simulation technology can be adopted to improve the interpretation accuracy of gravity-magnetic data. The principles of the technology are as follows: ①the initial space structure of geologic model is established by horizons interpreted for seismic profiles; ②the spatial density is obtained by the equation of seismic wave velocity and formation density; ③the occurrence of igneous rock and the fluctuation of magnetic basement are judged by magnetic source depth estimating method; ④by fitting different physical elements, the gravity-magnetic multi-parameter simulation technology is used to adjust the density difference, magnetic capacity difference, and boundary of modeling geologic body and to identify the geologic structures as well as its attributes details. The method was used to do integrated fitting of physical elements of LJ line in Huangqiao area, including gravity-magnetic observation field, high-frequency filtering field, low-frequency filtering field, pass-frequency filtering field, derivative and gradient, etc. The fitting greatly restricted the range of solutions and improved the accuracy and credibility of gravity-magnetic data interpretation.