Abstract: Switchable molecular electronic devices, which are triggered by electrostatics interactions or UV light, have potential applications in data storage, drug delivery, cell culture, biosensor and tissue engineering. By using quantum chemical calculations and molecular dynamics (MD) simulations, we investigated the conformational change and switching process for several kinds of electro-controllable surface-supported molecular switches. The polarizable force field based MD simulations were carried out to study the switching behavior of a series of oligopeptides on gold surface under the control of electric fields. The oligopeptide chains will extend or fold driven by the electric field, showing ON and OFF switch, which is in agreement with the experiment. By using reactive molecular dynamics simulations, we investigated the conformational change and switching process for several kinds of electro- and light-controllable surface-supported molecular switches.