ABSTRACT: With the wide application of HVDC, HVDC transmission line protection is becoming more and more important. In this paper,a DC transmission line based electric transient protection method that based on fault current and voltage high frequency wavelet energy mutation characteristics is proposed.The principle using the based information does not depend on the communication and would action more quickly. The simulation results show that, protection can operate correctly in all situations, have great resistance to transition resistance ability ,and high selectivity.