The invention provides a gas detection device based on a dot matrix type piezoelectric thin-film sensor. The gas detection device comprises a dot matrix type piezoelectric thin-film sensor, a signal generator and a signal acquisition and analytical processing module, wherein the dot matrix type piezoelectric thin-film sensor comprises at least one gas channel; each gas channel comprises a plurality of piezoelectric films; the plurality of piezoelectric films are arranged on a substrate to form a dot matrix type sensor group; the piezoelectric films are made of photonic crystal materials, and sensitive materials capable of adsorbing to-be-detected gases are applied to inner surfaces of the piezoelectric films; the signal generator is connected with the dot matrix type piezoelectric thin-film sensor; and the signal acquisition and analytical processing module is connected with the dot matrix type piezoelectric thin-film sensor. According to the gas detection device disclosed by the invention, resonance wave generated by the signal generator are focused by adopting the piezoelectric thin-film sensor of a dot matrix type structure, the amplitude and efficiency generated by the signal generator are amplified, and the detection accuracy is improved. Moreover, the gas detection device can be applied to detecting different types of gases in different fields and is high in sensitivity and wide in application range.