A micro-structure ethanol gas sensor on a silicon substrate based on the nano complex oxide La0.7Sr0.3FeO3 was successfully designed and fabricated. The heater electrode and signal electrode were designed on the same plane in order to reduce the cross-talk and make the fabrication easier. The results of the simulations are used to improve the temperature distribution on the sensor. Compared to classical sintered gas sensors, the optimized design leads to a low power consumption. The experimental results show that the power consumption is approximately two thirds of the sintered gas sensors with the same active material. The sensitivity of this novel sensor is 8.0 when the concentration of ethanol is 500 ppm, and the response time is about 1.5 s and the recovery is about 2.5 s. (c) 2007 Elsevier Ltd. All rights reserved.