Abstract: For the problem of great series motional resistance in Micromechanical (or MEMS) disk resonator, a novel moving-electrode approach is presented to reduce the electrode-disk gap and the series motional resistance of resonator. This approach introduces the tunable property of other RF MEMS devices to disk resonators in the existing fabrication conditions. The series motional resistance of the disk resonator is reduced. The paper introduces the theory and design of the disk resonator with suspended electrode, derives the effective gap width after electrodes moving, proposes a circle-shaped groove produced by hole in a mask to solve the point contact problem between electrode and disk and analyzes the effect of circle-shaped groove on the effective gap width. In ANSYS10.0, the suspended electrode is pulled in the fixed bar with voltage of 2.10 V (0.1 m) or 66.38 V (1 m) and gap of 0.0016 m or 0.01 m. For 0.1~1.1 m gap resonator, the series motional resistance drops below its10-8 times.