Hierarchical tin oxide(SnO2) architectures were synthesized with a facile hydrothermal method. In the hydrothermal synthesis, sodium dodecyl benzene sulfonate(SDBS) surfactant plays an important role as struc- ture-directing reagent. The synthesized samples were characterized by powder X-ray diffraction(XRD), field emis- sion scanning electron microscopy(FESEM), transmission electron microscopy(TEM) and high-resolution transmis- sion electron microscopy(HRTEM). The results clearly reveal that the hierarchical architectures of SnO2 were com- posed of aggregated nanosheets with a thickness of about 100 nm. A possible mechanism for the formation of the SnO2 hierarchical architectures was proposed. In addition, the gas sensing properties of the as-prepared products were investigated and it was found that the sensor based on the special SnO2 hierarchical architectures exhibited a high re- sponse and good selectivity to NO2 at the optimal working temperature of 160 ℃.