The MEMS hydrogen sulfide gas sensor is composed of a Si-based micro-hot plate made of MEMS technology and a metal-oxide-semiconductor material with low conductivity in clean air. When the detected gas is present in the ambient air, the conductivity of the sensor changes. The higher the concentration of this gas, the higher the conductivity of the sensor. The change in conductivity can be converted into an output signal corresponding to the gas concentration using a simple circuit.