Aim to the main supervision and control function of synchronous generator excitation system, remote supervision technology based on web of excitation system is implemented by AJAX at first. The designed supervision system can be accessed by browser on PC and intelligent phone under the environment of local or internet network. Then a remote real-time supervision and control method based on TCP/IP and VPN technologies is presented in the case of unstable real-time data transport of internet network, and the feasibility and validity is confirmed by the experiment.