A typical double-side capacitive micro resonator is considered， and delayed velocity feedback is proposed to apply on DC bias voltage of its vibrating system to control its complex dynamical behavior. By inducing new variations， the heteroclinic orbits and homoclinic ones of the unperturbed system are expressed analytically. On this basis， the mechanism and the effect of the delayed feedback on controlling the global bifurcation are studied. It is found that delayed velocity feedback control is effective in suppressing pull-in instability of the microstructure but unsuitable to control chaos， which has some potential values in improving the global integrity of electro-static micro mechanical systems.