In order to solve the problem of unstable communication in wireless magnetic induction communication system due to the change of the attitude of the receiving coil, this paper proposes a method of using three mutually orthogonal coils at the receiving end to make up for the weakness of the communication fluctuation of a single coil. Firstly, the mathematical model of single coil and omnidirectional coil is established, and the law of magnetic field size and induced voltage at the receiving end is analyzed. Finally, the feasibility of the method of receiving coil as three-dimensional orthogonal coil is verified by simulation and experiment. The simulation and experimental results show that the three-dimensional orthogonal coil as the receiving coil can effectively improve the induced voltage value in the wireless magnetic induction communication system, improve the stability of the communication channel, and reduce the volatility by 95%.