Abstract: This paper studies transmission characteristic of electronic current transformer (ECT) shunt for flexible HVDC. It firstly introduces working principles of ECT. The impacts of temperatures and skin effect on measurement errors is analyzed. Then according to the ECT in engineering application for flexible HVDC, the simulation model in PSCAD/EMTDC is established. Finally, study transmission characteristic by measuring current of the Nan’ao flexible HVDC system as well as changing critical parameters of the model. Simulation results indicate main reasons for causing measurement errors are temperatures and skin effect. It is able to obviously reduce measurement errors due to skin effect by reducing shunt conductor radius.