Multiplefield coupling is a typical characteristic of most mechanical structures in microelectromechanical system (MEMS), that involves the effects due to mechanical, electrostatic, magnetic, thermal actions, etc. Dynamic behaviors of the microstructures in those fields are of importance to estimate the design and manufacturing of the microsystem. In this paper, electromechanical analyses of some microstructures are presented based on a combination of boundary element method (BEM) and finite element method (FEM), to show the hybrid numerical technique not only useful to analyze the flexible deformation of the structures under electrostatic forces, but also important to evaluate the parameter variations of the electronic fields as the movement of the mechanical structures in those structronic systems. The simulation procedure is verified by both analytical solutions of some examples and experimental results of some microstructures driven by electrostatic field, in which the mechanical parameters such as the divergence of the deflection solution is related to the electrical characteristic such as the critical voltages of the electrostatic forces. Based on the structures involved in a laterally vibratory polysilicon gyroscope fabricated in our institute, the control equations of microgyroscope dynamics are presented, from that the response simulations of the microgyro are performed with the changes of the characteristic parameters, such as resonant frequency, quality factors, frequency disturbance, etc. Those results are useful for the optimal design of the structronic systems and the quality evaluation of the microprocessing, which are related to the rate measurement sensitivity and the output stability of the microsystem.