In different environments, high concentration of n-butanol will have certain harm to the human senses and nervous system, meanwhile the electrochemical sensor limits its widespread use due to its high power consumption, so it is very meaningful to develop a semiconductor n-butanol sensor with low energy consumption. In this paper, α-Fe2O3 nanorods were prepared by one-step hydrothermal method and then assembled into a n-butanol sensor capable of detecting n-butanol, and the effects of two different calcination temperatures on the performance of the sensor were investigated. Due to its higher Fe3+ content, higher oxygen vacancy content and larger specific surface area, S1-250 provided more active sites for gas adsorption, which making the response of S1-250 to 100 ppm n-butanol at 215 °C reached to 88.4. Finally, the effect of the calcination temperature on the sensor and the response mechanism were discussed. This paper offers promising applications for low-energy n-butanol sensors assembled from a single material α −Fe2O3.