Abstract: Aiming at the problems of poor real-timeness, insufficient coverage and others of safety monitoring systems under downhole complex geological conditions in coal mines, a wireless sensor network architecture based on layered heterogeneous is proposed. Through a three-level collaborative mechanism of wide area coverage in the backbone layer (LoRa), dynamic routing in the aggregation layer (ZigBee), and dense perception in the access layer (BLE), combined with information channel resource optimization and node energy consumption balance strategies, a topologically elastic and reconfigurable transmission system is constructed. The actual deployment verification results indicate that when the scheme dealing with roadway deformation and equipment vibration scenarios, the signal coverage rate is significantly improved to over 97%, the end-to-end transmission time delay is effectively controlled within 5 seconds, and the false alarm rate caused by environmental interference is significantly reduced by 89%. Its layered design cleverly balances the network coverage depth and energy consumption efficiency, providing high reliability technical guarantee for key application scenarios such as deep mine gas monitoring, roof displacement early warning and others.