Line parameter identification plays an important role in accurately reflecting the actual running state of a power grid, but it requires high precision of phasor measurement unit (PMU) data, so the measured data cannot directly meet the application requirements. Therefore, a transmission line parameter identification method based on PMU error correction is proposed in this paper. First, the PMU data is pre-processed based on categories using different error types and data characteristics. Then, given the bias error lacking significant features, a PMU error correction method based on physical equivalent model of transmission line is proposed. This considers the data law and error sensitivity characteristics. Finally, on the basis of the above correction method, a data quality governance program of the whole PMU station is proposed. Through simulation and measured data, the results show that the method proposed can improve the quality of PMU measurement data compared with the existing methods, and then realize the effective identification of transmission line parameters. This work is supported by the Science and Technology Project of State Grid Corporation of China (No. 524609210084).