The present disclosure relates to a capacitance variation detection circuit, a touch screen and a touch detection method. The method includes: connecting one terminal of a detection capacitor and one terminal of a denoising capacitor to a first power simultaneously, and connecting the other terminal of the detection capacitor and the other terminal of a denoising capacitor to a reference ground simultaneously; disconnecting the detection capacitor from the first power source and connecting it to the negative input terminal of the operation amplifier, switching the one terminal of the denosing capacitor from being connected to the first power source to being connected to the reference ground, and connecting the other terminal of the denoising capacitor to the negative input terminal of the operational amplifier; and acquiring an output result of the operational amplifier, and judging whether there is a touch operation according to the output result.