Taking the Lijiaxia Dam as an example, 4 typical phenomena of high concrete arch dams during long term operation are summarized and analyzed, including the large deformation of dam foundation, the asymmetric deformation at the left and right 1/4 part of the arch, uplift pressure anomaly at the elevation of 2087 at the left and right part of the dam, and the high ground temperature. The behavior of the Lijiaxia Dam was estimated by using high water level prototype test, forward and back analysis, FEM analysis of the observed data with the help of regularity analysis, correlation analysis, generalization and summarization. The results show that the variation of the horizontal displacement of the Lijiaxia Dam is normal as a whole with good operation conditions and the design demonstration and evaluation is normal. After treatment of the dam foundation, it satisfies the safety requirements with sufficient overload safety.