Maintenance method of gas detecting device

A maintenance method of a gas detecting device, comprising:

• providing the gas detecting device, the gas detecting device including a shell component, a sensing component, a dust blocking element, and a detecting area, the sensing component and the dust blocking element being disposed in the shell component, and the sensing component and the dust blocking element being disposed corresponding to the detecting area, wherein the sensing component includes a sensor, a reference light source, and a processor, the processor is electrically connected to the sensor, the dust blocking element includes a cover, and the cover is light permeable;
• generating a reference beam projecting toward the cover and the detecting area through the reference light source, the reference beam generating a feedback beam projecting toward the cover and the sensor through being reflected by a part of the shell component positioned at the detecting area;
• receiving the feedback beam through the sensor to generate a measured information;
• and
• comparing the measured information to an initial information stored in the processor through the processor, so as to obtain a pollution degree information of the cover.