With the construction and development of power system, the structure of power grid is becoming more and more complex. Due to the long-term operation of power lines and changes in the surrounding environment, deviations exist between the original line parameters model and the actual line parameters, which affect the real-time monitoring and optimal operation of power system. Considering the sufficient measurement of data acquisition and monitoring system(SCADA) in power system transmission lines, a line parameter identification model is presented based on multi-innovation least squares(MILS) algorithm in order to achieve accurate identification and correction of the whole network lines. IEEE 39-bus power system simulation model is built on real-time digital simulation(RTDS) platform to obtain power flow operation data. Then, parameter identification is carried out in Matlab environment, and the identification results are compared with the line parameters on RTDS platform. The results show that the parameters identification results based on MILS algorithm have high estimation accuracy, and can be used as the basis for judging suspicious lines in power system.