The invention discloses a flexible capacitance type humidity sensor which is characterized by comprising a flexible substrate (1), an electrode (2) and a humidity-sensitive material layer (4), wherein the electrode (2) is arranged on one surface of the flexible substrate (1); the humidity-sensitive material layer (4) is arranged on the other opposite surface of the flexible substrate (1); the electrode (2) and the humidity-sensitive material layer (4) are separated by the flexible substrate (1); the electrode (2) is led out by a wire. In the flexible capacitance type humidity sensor provided by the invention, the manner of coating a sensitive material on the rear side is adopted and an electrode protecting layer is arranged, so that the electrode is prevented from being oxidized after absorbing water, the measurement error caused by the electrode which adsorbs water can be prevented, the measurement accuracy can be increased, the service life of the sensor can be prolonged and the stability of the sensor can be enhanced. The adopted PET material is excellent in softness, can be randomly bent and is suitable for a plurality of fields.