Abstract: At present, remote peer-to-peer firmware updates have been implemented in the multi-layer heterogeneous network of coal mines, but the firmware of devices at all levels cannot be directly updated from the ground control host. The maintenance workload is relatively large when the sensors are distributed and the number is large, thus a remote firmware update method for multi-layer heterogeneous network of coal mines with unlimited levels and multiple links is proposed. The method is proposed that the host sends the firmware and its routing, and devices at all levels parse the routing, forward the firmware or update itself. The update process can display its progress information. The characteristic features of the firmware data in multilayer heterogeneous networks is transferring through multiple devices and links to reach the target device. This paper is proposing that the core of realizing remote firmware updates in multi-layer heterogeneous networks lies in routeing description. Moreover, this paper studies the method and process of realizing routing description by using JS object notation (JSON) from three aspects: device property description, network topology construction and firmware routeing description. The lower and upper computer software design method for implementing remote firmware updates of multi-layer heterogeneous networks in coal mines is introduced. A four-layer heterogeneous network experimental system containing Ethernet, RS485 bus and CAN bus is built, and the feasibility and stability of the JSON routing description based remote firmware update method for multi-layer heterogeneous networks in coal mines is verified by the statistics of the success rate and update time of each layer device firmware update.