The invention provides a plasma pressure sensor. The plasma pressure sensor comprises a discharge electrode, wherein the discharge electrode comprises two metal electrodes and two insulating block media arranged on the surfaces of the metal electrodes, and plasma is produced between the two insulating block media by the discharge electrode under the driving of an alternating-current power supply.Meanwhile, the invention provides a plasma pressure sensing system. The plasma pressure sensor and the plasma pressure sensing system can reduce cathodic sputtering, are not affected by mass inertia,have potential of breaking through MHZ high-frequency response, can effectively reduce cathodic sputtering of electrode surfaces and prevent electrode loss.