Abstract: Temperature load is one of the main design loads of the arch dam, which is closely related to closure grouting temperature and environment temperature and water temperature of reservoir. However, there are some differences between the actual temperature loads and the design temperature loads. As the traditional point thermometer monitoring data is far from enough, it is difficult to make reasonable and effective feedback of the arch dam temperature load. Combining with the measured temperature monitored by a distributed optical fiber placed on a typical dam section of the Xiluodu high arch dam, based on a moment method, the actual temperature load of the high arch dam got feedback. The equivalent temperature can be expressed by polynomial with the moment method. Based on the equivalence principle of moments of the equivalent temperature and the measured temperature given by the distributed optical fiber, the coefficients of the polynomial and distribution of the equivalent temperature can be obtained. Analysis results show that the whole cross-section of the equivalent linear temperature in the existing specifications is only a special case of the nonlinear equivalent temperature which is 1 moment. By calculating 2 and 3 moments equivalent temperature of the actual temperature and obtaining the nonlinear temperature distribution of the dam sections, the adjustment process of the arch dam temperature from the closure grouting to the normal operation can be more fully understood, and it can provide a useful supplement to the arch dam design.