The present disclosure provides a touch detection chip and a touch screen detection method. The touch detection chip includes: a signal output unit configured to output a driving signal to a first channel of a touch screen; a first analog front end circuit, an inverting input end of which being connected to the first channel; a second analog front end circuit, an inverting input end of which being connected to a second channel of the touch screen; an impedance-adjustable circuit connected between a non-inverting input end of the first analog front end circuit and the signal output unit; a DC voltage unit connected to a non-inverting input end of the second analog front end circuit; and a processing unit separately connected to the signal output unit, the first analog front end circuit and the second analog front end circuit.