The polymers with various composition of 4-vinylpyridine (4-VP) with n-butyl acrylate (n-BA) and 2-hydroxypropyl methacrylate (HPMA) were synthesized as a humidity sensitive material and quaternized with 1.5-dibromopentane. Resistance versus relative humidity decreased with increase in the content of n-BA in the copolymer. The introduction of HPMA increased the resistance of the humidity sensor as well as enhanced the adherence to the alumina substrate. In the case of 4-VP/n-BA/HPMA=80/10.10, the hysteresis and temperature coefficient were $pm$2%RH and -0.42∼0.46%RH/$^{C}$. The average resistance at 30%RH, 60%RH and 90%RH are 3.1㏁, 155 ㏀ and 7.9 ㏀, respectively.