In order to sum up the characteristics and laws of seismic damage of water conservancy and hydropower engineering within the great earthquake, i.e. the magnitude Ms 8.0 Wenchuan earthquake occurring on 12 may 2008, the authors made field surveys and collected the data on geological conditions of the dam foundation, seismic damage characteristics, anti-infiltration types, engineering treatment measures and so on, of large-, medium- and small-sized water conservancy and hydropower engineering in highly seismic region where the seismic intensity was greater than 8. After classification and statistics, the laws are as follows: The dam body composed of the rigid materials was more severely damaged than that built by the flexible one; the vertical deformation of dam body was proportional to the filling height, while the dam height was 156 m, the maximum vertical deformation was 744.3 mm ； the horizontal displacement was no significant relationship with dam height ； the destructive deformation of dam was decreased form up to down ； the treated slopes produced less earthquake damage while the untreated slopes occurred some slides and slumps ； the destruction of caverns was not obvious and so on. These results accumulated invaluable experience for earthquake seismic design in the construction of southwest China ' s water conservancy and hydropower projects. It provided a reference for the amendment of “ Specifications for Seismic Design of Hydraulic Structures ” .