|A molybdenum disulfide sensor includes a flexible substrate, a patterned circuit layer and at least a molybdenum disulfide sheet. The flexible substrate has a gas flow channel. The patterned circuit layer is formed on the flexible substrate, and the patterned circuit layer includes a first electrode and a second electrode. The second electrode is faced toward the first electrode, and a gap is formed between the first electrode and the second electrode. The molybdenum disulfide sheet is located in the gap and is connected with the first electrode and the second electrode.