Following the progresses in construction technologies and developments in construction of important structures, which cost a lot for the developers, monitoring the efficiency and performance of structures has become more important. Also, since many of the structures that were built several decades ago are Still in service, but sometimes their performance is not perfect any more. Ensuring the perfect performance of high-value structures, such as historic structures or vital buildings, and bridges, railways or highways and roads are essential.Monitoring the performance of the structures in general procedural sense to provide accurate information about the status of the structure and its effectiveness, which can be investigated in the short or long term.These methods are categorized to dynamic and static identification methods. The purpose is to compare the parameters of the analytical or numerical model with the measured data and their correspondence with each other. It can be witnessed the constant monitoring of important structures in the developed countries of the world, but in Iran, these studies are at the beginning.in this paper after explaining the bases of performance monitoring of the structures, results of performance monitoring of the Sadra Bridge in Shiraz-Esfahan Railway though loading test are described.