A method and system for predicting the quality factor of a mechanical resonant (MR) device. The system and method simulates uncoupled elastic vibration of the MR device to produce simulated dilatation and collects data relating to the dilatation and maximum stored elastic vibration energy. It determines the internal heat source data of the MR device caused by dilatation based on the thermal expansion effect of the MR device material, conveying the internal heat source data along with transient heat conduction data to a simulation engine, which simulates and determines the temperature variation. Thermoelastic damping over one cycle of vibration is determined, enabling the prediction of the quality factor relating to thermoelastic damping over one cycle of vibration of the MR device, and the maximum elastic vibration energy stored over one cycle of vibration.