Abstract: The belt conveyor self-checking roller installs wireless sensor nodes inside the roller to collect and wirelessly transmit temperature and vibration signals, which provides a new idea for the health checking of coal mine belt conveyor rollers. In order to solve the energy supply problem of the wireless sensor nodes in the closed roller, an energy harvester based on the Halbach permanent magnet array is designed. This paper introduces the structural design of the energy harvester, and analyzes the energy supply requirements based on the actual energy consumption of the wireless sensor nodes and the efficiency of the energy management circuit. COMSOL Multiphysics 5.5 is used for finite element analysis of the energy harvester to verify that Halbach permanent magnet array has obvious advantages over conventional permanent magnet array when used in small rotating body energy harvesters. The effect of air gap thickness, permanent magnet thickness and rotor speed on the power generation performance of the energy harvester is analyzed. And it is concluded that the induced voltage of the energy harvester can be increased effectively by reducing the air gap thickness, increasing the permanent magnet thickness and increasing the rotor speed. Based on the analysis of energy supply demand, installation space requirement and finite element analysis, the parameters of the energy harvester are optimized, and a prototype is built for testing. The results show that at 5 r/s rotor speed, the effective value of the induced voltage of the energy harvester is 4.77 V, the maximum power is 171.33 mW, and the power density is 6.78 mW/cm3, which meets the energy consumption requirements (165.722 mW) of wireless sensor nodes.