Abstract: It is hard to use conventional theories and methods to deal with the problems of irrigation and drainage engineering at present, because the modern irrigation and drainage engineering is a complex system with multi-stage, multi-objective, multi-level, multi-attribute and multi-function. Computational intelligence(CI) is one of the most highlight fields in artificial intelligence technology nowadays. The rapid development of CI and increasing complexity of irrigation and drainage engineering attribute definitely to the combination of CI and the ancient, as well as modern, engineering of irrigation and drainage system. In this paper, a brief presentation on the development of irrigation and drainage engineering and the basic concept of CI is given firstly. Then, some of the frequently used theories and methods of CI, such as fuzzy sets(FS), artificial neural networks(ANN), genetic algorithms(GA), simulated annealing(SA), rough sets(RS) and chaos theory etc. and their applications on the system programming, modeling construction, forecasting, engineering design, comprehensive evaluation and running optimization of irrigation and drainage engineering are separately introduced and discussed. Finally, the existing problems and future application of CI on irrigation and drainage engineering are proposed.