The yield of the traditional sandwich-type sensor is badly influenced by the micro holes in the film caused by the by-products of the imidization reaction. The Capacitive-type humidity sensors with Si-SiO_2-PI structure were prepared and the properties were studied. The properties were compared with those of the traditional sandwich-type sensor. The results showed that the capacitance is increased by 25%; the sensitivity reaches 1.24 pF/%. Short circuit caused by the micro holes in the film has been minimized. The sensor suits for mass production.