The invention relates to a humidity detection circuit and belongs to the technical field of a humidity sensor. The invention aims to solve the problem that the humidity detection is unstable because the humidity sensor changes along with the change of the temperature under low-temperature environment. The humidity detection circuit provided by the invention is arranged as a humidity measuring circuit based on a capacitance charge-discharge and comparison method, so that the temperature drift and the zero drift are effectively restrained and the influence of stray capacitance on measuring result is reduced. The humidity detection circuit is applied to the humidity sensor.