Abstract: Thick film humidity sensors were prepared by the screen-printing technique starting from Zn₂SnO₄-LiZnVO₄ system nanometer powders obtained by Sol-gel method.Compared with other sensors made by ordinary ceramic powders, the humidity sensor has the advantages of lower resistance atlower humidity and long-term stability. Properties measured at different operating frequencies indicate that the sensor has the characteristic of linear sensitivity at 1 kHz. The results of complex impedance analysis indicate that better microstructure resulted from nanometer powders and sintering at proper temperature is the reason of better properties for the humidity sensors.