The present disclosure provides a measuring device, a measurement system, and a measuring method for a dielectric constant of a liquid crystal. The measuring device includes: a first substrate and a second substrate opposite to each other; a conductive layer disposed on a side of the first substrate facing the second substrate, wherein the conductive layer is configured to receive a first voltage signal; a resonant structure layer disposed on a side of the second substrate facing the first substrate, the resonant structure layer being configured to receive a second voltage signal and configured to transmit the microwave signal; a frame disposed between the first substrate and the second substrate, the frame cooperating with the first substrate and the second substrate to form a cavity for accommodating the liquid crystal to be measured.