Abstract: In view of requirements of security and environmental monitoring in coal mine multiplex medium in challenging environment, in order to conquer the obstacles such as serious path loss, dynamic channel condition and constrained supply condition and so on, theory model of wireless magnetic induction communication and magnetic induction waveguide communication in multiplex medium was proposed, and structure of wireless magnetic induction sensor network was given. Research directions and application of wireless magnetic induction sensor networks in the future were prospected, the urgency of related study was pointed out. It has great significance to safety monitoring of underground environment and the oil, gas or water pipeline which is especially long or in densely populated area.