The invention provides a potentiometer with three-range switching for DC voltage measurement, which includes three ranges of X10, X1 and X0.1, wherein 20X40 / 11 Omega is used as a No:1 measuring disc, 10X0.4 Omega is used as a No:2 measuring disc, 0-4.4 Omega is used as a No:3 measuring disc, the three measuring discs are connected with wires, thus no contact resistance and variation exist, the zero potential produced by the lead wire resistance is compensated through the negative potential, in the X10 range, its high measuring limit is 211mv, in the X0.1 range, its minimum resolution is 0.1uV, and good measurement reproducibility can be achieved.