In this paper, ZnFe2O4 microspheres with two different morphological structures were prepared by template-free solvothermal reaction: nanoparticle assembly and nanosheet assembly. Gas-sensitive materials are comprehensively analyzed through various characterization techniques, covering a wide range of aspects from microstructure, elemental composition, valence analysis to specific surface area. Then, the gas-sensitive properties of ZnFe2O4 gas sensors with two different microstructures for target gases were experimentally tested. The experimental findings demonstrate that the porous microsphere configuration of ZnFe2O4 exhibits superior response capabilities to 100 ppm of isopropanol at 240 °C. This suggests that, the porous microspheres ZnFe2O4 have the potential to be a superior gas-sensitive material to detect isopropanol.