Abstract: The content of dam safety monitoring and controlling can be divided into several parts as following, it includes study on the dam safety monitoring instrument and technical methods，error management of observational data and analysis, normal analysis on observational data，back analysis on observational and dam structure condition, dam safety comprehensive judgement and decision, development and study on dam safety intellectualized system and so on. The study above on every aspect has interacted each other, which construct the frame of dam safety monitoring and controlling theory and technology. This paper will state the actuality of study and trends on dam that.