Volatile organic compounds (VOCs) are organic compounds characterized by boiling points below 250 °C at standard atmospheric pressure (101.325 kPa). VOCs serve as critical biomarkers for non-invasive medical diagnostics and food safety assessments. Consequently, the development of high-performance gas sensors capable of detecting these VOCs with high sensitivity is of paramount importance. However, current gas sensors exhibit limitations in sensing performance, including elevated operating temperatures and inadequate selectivity. To address these challenges, our research focuses on the design and synthesis of mesoporous semiconductor metal oxide spheres, along with the modulation of pore microenvironments to optimize the adsorption, conversion, and desorption processes of gas molecules. We introduce a self-template strategy to precisely tailor the internal porous structure and compositions of semiconductor metal oxides (e.g., SnO₂ and ZnO). By incorporating rare earth elements, constructing heterojunctions, and decorating these materials with noble metal nanoparticles or single atoms, we have fabricated a series of advanced semiconductor metal oxide gas sensors. These sensors demonstrate superior sensitivity, enhanced selectivity, and reduced working temperatures for various gases, including ethanol, formaldehyde, triethylamine, trimethylamine, and 3-hydroxy-2-butanone. Moreover, wireless gas sensors have been developed for real-time monitoring of the release of VOCs in different environments. We will focus on the gas sensors applied in breath analysis and food safety monitoring.