Abstract: Crest settlement reservation of concrete face slab rockfill dams would effect flood prevention safety and visual image.Some dam crest elevation was found lower than design in operation as there was no settlement reservation in design, while some recorded settlement in operation exceeded the designed value as the settlement reservation in design was too small. By statistics of dams, the recorded settlement value was more than 0.1% of damheight. For enough settlement reservation in operation and good visual image of arch at middle part, settlement reservation no less than 0.5% of damheight was recommended.