Gravity and magnetic method exploration in mining was widely used with relatively low cost, the technology played an important role in buried mine positioning and target section optimization. Magnetic interpretation was with multiplicity of solution in practice, corresponding measures were taken to reduce the multiplicity of solution, geological limiting inverting was commonly adopted. 3 d density mapping technology research was taken as ultimate goal, through mold experiment to see if there was inversion effect under constraints, the result showed that 3 d density mapping technology with geological information constraints could explore deep mining.