In a demodulation system for a low-power differential-sensing capacitive touch panel, the capacitive touch panel has n first conductor lines in a first direction and m second conductor lines in a second direction, and a mutual capacitance is generated at each intersection of the n first conductor lines and the m second conductor lines. The demodulation system has a signal generator, a detection circuit, a programmable gain amplifier, an analog to digital converter. During a driving cycle, the signal generator generates a pair of differential driving signals to drive two of the first conductor lines in the first direction for eliminating common noises of the two first conductor lines and avoiding the common noises from being amplified by the programmable gain amplifier.