Abstract: Novel bulk ZnO porous nanosolids were prepared by Hydrothermal Hot-Press （HHP） tech- nique, using ZnO nanoparticles （with average particle size of 30 nm）. At the same time, ZnO nano- particles were treated with conventional hydrothermal method （pretreated ZnO nanoparticles）. then,two kinds of thick-film gas sensors were prepared by using ZnO porous nanosolid and pretreated ZnO nano- particles, respectively. The intrinsic resistances of the gas sensors were tested. Compared with the sensor fabricated by ZnO nanoparticles, the intrinsic resistances of the above two kinds of gas sensors decrease greatly. It’s good for improving the stability of the sensors. The differences in the intrinsic resistances of the thick-film gas sensors are analyzed based on the SEM and TEM measurements.