Aiming at the serious problem of spur dam damage and the current lack of stability calculation，this paper analyzes the characteristics and causes of spur dam damage under flood based on the investigation report of spur dam damage in Jialing river channel，and establishes the spur dam by combining theoretical analysis.The calculation model of the stability of the block rock in different parts of the surface and the calculation model of the overall anti-slide stability of the spur dike.From the stability calculation results of the dam face stones，the stability of each part can be obtained as the back slope of the dam body，the head slope of the dam head，the back slope of the dam head，the crest，and the back slope of the dam body.The overall stability calculation results are relatively designed.The calculation results of the hospital are more reliable.