The embodiment of the invention discloses a potential measuring device. The potential measuring device comprises a fluid measuring device, a fluid driving device and an electric signal testing device, wherein the fluid testing device comprises a pressure bearing cylinder and a testing cylinder; the testing cylinder is arranged in the pressure bearing cylinder, and a cavity for containing testing fluid is formed between the pressure bearing cylinder and the testing cylinder; the pressure bearing cylinder comprises a first body, a first opening, a second opening and a third opening, the first body is relatively sealed, the first opening is arranged on the first body and is used for air exhaust, the second opening is used for air intake, and the third opening is used for liquid intake; the testing cylinder comprises a second body, a first electrode and a second electrode, and the first electrode and the second electrode are arranged in the second body at preset distance; the fluid driving device is respectively communicated with the pressure bearing cylinder through the second opening and the third opening; the electric signal testing device comprises a voltmeter, a differential pressure meter and a capacitance measuring device. The potential measuring device can be used for measuring the Zeta potential of a micro-dispersion oil driving system at pressure higher than normal pressure.