Abstract: Concerning Ansha Dam’s 3# section’s relatively poor geological condition, peculiar cross-section shape relatively large annual variation arrange of crest-horizontal-displacement, analysis based on thin-layer-unit FEM is carried out, concrete integrated elastic-modulus is calculated, compound model is set up, and calculation of intensity and stability is performed, which concluded that the 3# section’s structure and working state is normal and provides reference for dam safety operation.?