Hierarchical SnO2 aerogels have attracted a wide interest for their semiconductivity. In this work, we synthesized the MoO3-mixed SnO2 aerogels via facile ambient pressure drying (APD). Simultaneously, the ethanol-sensitive property of MoO3-mixed SnO2 aerogels was studied, expected to explore their possible electrochemical applications in the future. Particularly, after the MoO3-mixed SnO2 aerogel was calcined in nitrogen, it showed a high response value (Ra/Rg) of 714 to 100 ppm ethanol at 260 degrees C. Besides, it also had characteristics of low response concentration, rapid response time and unique selectivity to ethanol. Combined with the analysis of various techniques, the mechanisms for gas-sensitivity have been discussed. The results demonstrate why MoO3-mixed SnO2 aerogel calcined in nitrogen has excellent gas-sensitivity to ethanol can be ascribed to its additional depletion layer and favorable hierarchical structure.