According to the medium filled, rubber dam is divided into air inflatable rubber dam and water filling rubber dam: Water filling rubber dam: it can lower the temperature of surface of rubber bladder to extend its service life in summer. Air inflatable rubber dam: it will not be frozen in the cold region. According to the slope, rubber dam is divided into pillow rubber dam and inclined rubber dam: Fin rubber dam: The cross-section of fin rubber dam looks like a book with smooth appearance. The fin erects when inflated to form a rising angle to raise the water head during a certain overflow, and eliminate vacuum underneath the dam with certain depth of flow water, thus reducing the vibration and wearing out of the rubber bladder.