A signal processing method is employed to operate a touch panel having a first touch sensing unit and plural second touch sensing units adjacent to the first touch sensing unit. In the operation of the method, a first signal is generated through amplifying the first sensing signal of the first touch sensing unit by N times with N equal to the number of the second touch sensing units, a second signal is generated through summing up the second sensing signals of the second touch sensing unit, a difference signal is generated through subtracting the second signal from the first signal, a comparison result is generated through comparing the difference signal with a difference threshold, and finally the comparison result is utilized for judging whether a touch event is occurring to the first touch sensing unit.