Abstract: In Zhangjiawan iron deposit，controlled source audio-frequency magnetotelluric sounding was used to infer the occurrence characteristics of ore bodies，and the distribution model of ore bodies was established to solve the problem of deep prospecting. Firstly，according to the magnetic parameters of rock and ore，the effective magnetization intensity and magnetic inclination angle of the model are calculated， and the forward simulation of the model is carried out to verify the reliability of the model. The results show that the forward curve fits well with the measured curve，which proves that the controllable source ore body model is reliable. Through magnetic-electromagnetic joint interpretation，the problem of large error of deep iron ore interpretation by single magnetic method is solved，especially in areas with relatively complex geological conditions，which is not sensitive enough to reflect deep ore bodies and has multiple solutions. The accuracy of ore body interpretation is greatly improved，and better deep ore body interpretation results are obtained.

Key words: complex geology, deep iron ore exploration, magnetic-electromagnetic joint interpreta? tion, forward model