More than 87000 dams have been built in China,and about one third of them are risky projects.A number of high and ultra-high dams are being constructed in China’s western region.The current dam construction practice tends to focus on socio-economic benefits and neglect the environment and ecology.Furthermore,periodic examinations are intended to ensure the structural safety of dams.This paper proposes a general evaluation principle for dam service.This principle stipulates that dam projects should have maximum socio-economic benefits and minimum negative effects on the environment and ecology.To satisfy the general principle of mutual harmony,socio-economic benefits,dam safety,environment,and ecology are analyzed,and the evaluation methods for dam service status are discussed.Then,a fusion algorithm of interlayer assessment is proposed on the basis of evidence theory and the fuzzy comprehensive analysis method.Finally,a comprehensive evaluation model is established.Example analysis shows that the proposed theories and methods can fulfill scientific assessment of the service status of dams. More than 87,000 dams have been built in China, and about one third of them are risky projects. A number of high and ultra-high dams are being constructed in China’s western region. The current dam construction practice to focus on socio-economic benefits and neglect the environment and ecology. Future and periodic examinations are intended to ensure the structural safety of dams. This paper proposes a general evaluation principle for dam service. This principle stipulates that dam projects should have maximum socio-economic benefits and minimum negative effects on the environment and ecology. Serving the general principle of mutual harmony, socio-economic benefits, dam safety, environment, and ecology are analyzed, and the evaluation methods for dam service status are discussed. on the basis of evidence theory and the fuzzy comprehensive analysis method. Finally, a comprehensive evaluation model is established. Example analysis sho ws that the proposed theories and methods can fulfill scientific assessment of the service status of dams.