Researchers are showing significant interest in the development of nanostructures with hierarchical porosity. This study introduces an eco-friendly, cost-effective, and straightforward method to create SnO2 hollow porous nanostructures using the peony as a biotemplate. A comprehensive analysis of the gas sensing characteristics of these hierarchical SnO2 hollow porous nanostructures is conducted. The results show that the gas sensor based on SnO2 showcases relatively high response values measuring 18.3 and exhibits rapid response speed of 1 s to 100 ppm isopropanol, even at a comparably low operating temperature of 180 °C. Additionally, the sensor displays good repeatability and long-term stability, which can be attributed to the inherent advantages stemming from its distinct structure. Therefore, this study provides experimental and theoretical foundations for the potential application of hollow porous SnO2 structures in sensor technology.