Abstract:As the most important water retaining structure, the safety of dams is of great importance. In general, the security is judged according to the results of the internal monitoring, but if the measurement error is large, it will lead to the wrong conclusion, make the wrong judgment, and cause irreparable loss. Taking the dam safety monitoring of the Xiangbiling hydropower plant as an example, this paper puts forward the improvement of the current differential resistance instrument observation method, reduces the system error, ensures the reasonable data analysis, checks the measuring instrument by the positive and negative measurement of resistance ratio, optimizes the measurement results, improves the measurement precision, and eliminates the error in time, and the error is eliminated in time, and the error is eliminated, and the error is eliminated in time. The instrument check, the observation personnel only rely on experience, only according to the positive resistance ratio measurement, the error can be up to 10 units. After the analysis of the instrument, the measurement error can be controlled within 5 units, the accuracy is increased by more than 1 times, and the problems can be found in time, such as the aging of line joints, the corrosion and shedding of the steel wire, It leads to the distortion of the measurement results, etc,and some repair can be made according to the actual situation, which has a certain reference and promotion significance for the internal monitoring of other concrete double curved arch dams.