The invention provides a gas sensitive material and a preparation method thereof. The material comprises the following components, by mass: 100 parts of glucose, 5-40 parts of copper sulfate, and 1-20 parts of cesium nitrate. The gas sensitive material has a single selective response to carbon monoxide in mixed gas, can be applied to detection of decomposition gas of an insulating material in a substation, does not need to separate the decomposition gas, does not need a chromatographic column, and reduces the operation and maintenance cost of the substation.