Abstract: Dynamic rating technology of transmission lines can improve the transmission efficiency and transmission capacity of the existing transmission system to meet the increasing power demand and new energy integration needs. However, in order to ensure the safe and stable operation of the power system, extremely high requirements are put forward for the reliability of dynamic rating results of transmission lines. For the reliability problem of line rating, the main limiting factors of data acquisition technologies for transmission lines are analyzed, the advantages and disadvantages of different perception analysis methods are classified and compared, several application architectures of dynamic rating system are compared, and the cases are given to introduce the application of dynamic rating technology of transmission lines in actual projects at this stage. The research focus and limitations of the existing dynamic rating technology of transmission lines are pointed out from four aspects, i.e., data acquisition technology,perception analysis technology, system application architecture and engineering practice, and the future research areas are given accordingly.