The purpose of this paper is to describe a web-based system to assist on-farm design and management of surface irrigation systems. This application was designed to be an appropriate tool for generating design alternatives associated with attributes of technical, economic, and environmental nature, and handling and evaluating a large number of input and output data. It also allows the evaluation and ranking of design alternatives using multicriteria analysis where criteria are weighted according to the priorities and perception of the designer and users, and provides an appropriate dialogue between the designer and the user, with an effective help support with information about equipments and irrigation practices. The application has tools for the resolution of specific problems, such as land leveling, pipe sizing and economic calculation. Built with a simple user friendly interface, with several optional languages and online help for technical aspects, this tool will contribute to support the dissemination of knowledge, design procedures and field practices of surface irrigation. Tests and demonstrations are being done on Hetao Irrigation District, China.