In this paper, finite element method (FEM) simulations are used to model mechanical properties of MEMS resonators. Using a static displacement analysis the effective spring constant and mass are calculated. Nonlinearity of the mechanical restoring force is simulated to analyze large amplitude behavior of the resonator. Equivalent electrical circuit modeling is used for the simulating the frequency response of the resonators by APLAC RF-circuit simulator [1]. The FEM-calculated effective mass and spring constant are used to calculate equivalent electric circuit values. FEM and circuit simulation results are compared with the measured response of two example resonator structures; as an example we show detail analysis of clamped-clamped beam resonator operating at 1.6 MHz frequencies with Qvalue 30000. Mechanical non-linearities are included in the circuit simulation.