Along with RIA technology introduced in developing WebGIS,more and more events are used. Traditional way of event use has low efficiency and great mistakes,so it can’t meet practical needs.According to researching the mechanism of event process and the experience of WebGIS development,a new idea that all events should be managed totally was brought forward, and a framework of event manager was designed. Through the application in the LiaoHe River water environmental management system, it turns out that applying event manager simplifies the procedure of WebGIS development,avoids mistakable events, obtains satisfactory results. Also the framework of event manager is a good way to solve event management in traditional GIS and application program.