A remote robot control system was introduced, which is based on RIA (Rich Internet Application) technology and Flex platform. The system is comprised of two parts, which are the robot control module and the design module for foreground Web page application. This paper introduced the functions of each sub block, as well as the design of the programs. Meanwhile, the construction of the whole Web Service system has been specifically outlined. By using Flex technology, the system realized an asynchronous communication between Web and Web Service components， so that the real-time capacity has been greatly enhanced.