Abstract. In electronic devices field, there has been considerable interest in the study of organic substances such as phthalocyanines in thin film form for use as the active layer in gas sensor devices. In this paper, the device is simple manufacturing process, lower costs, and shows good Schottky characteristics. We use the vacuum deposition method and the organic semiconductor copper phthalocyanine or an organic gas-sensitive film make of the structure of Au (Emitte) / CuPc (organic gas sensors material) / Al (Base) / CuPc / Au (Collector) five-layer laminated structure organic transistor sensor. Tunneling CuPc / Al / CuPc Schottky Barrier barriers gate region formed due to the increase or decrease of the source emitter carriers, the working current is changed. Determination of the specific gas can be achieved by measuring the current change of the organic transistor sensor. It is successful implementation of the determination of NO 2 gas, and gas sensing sensitivity approximately 2.8.