A resistive input system is disclosed, which includes a resistor matrix. The resistor matrix includes M first traces, N second traces, and M*N resistors. First ends of the resistors of a same column are coupled to one of the M first traces, second ends of the resistors of a same row are coupled to one of the N second traces, M is integers greater than 1, and N is integers greater than and equal to 1. The M*N resistors include variable resistors. A measurement circuit measures variations of a first voltage level of each of the second traces while a power control circuit provides the first voltage to the one of the M first traces and the second voltage to the rest of the M first traces. At least one input point is determined according to the variation of the first voltage level of each of the second traces.