Poly-vanadium-molybdenum acid H

2

V

12-x

Mo

x

O

31±y

·nH

2

O（0≤x≤4.0） xerogel thin films humidity elements are prepared by sol-gel process

and its complex impedance plots are analyzed.Results show that the radius of semicircle of the complex impedance plots for poly-vanadium-molybdenum acid xerogel thin films increase with increasing of x.When x≥2.5

in the low-frequency range

the contact part of the total impedance for electrode appears.The properties of humidity elements are best as x=2.0

while the complex impedance is higher and no relationship with frequency.H

2

V

8.5

Mo

3.5

O

32

·nH

2

O xerogel thin film humidity element has good linear and high sensitivity in total relative humidity range at 1 kHz.