In　order　to　ensure　the　safe　operation　of　the　hybrid　double-ended　HVDC　transmission　system,　the　current　similarity　between　the　two　ends　of　the　hybrid　double-ended　DC　transmission　line　is　analyzed　in　this　paper.By　analyzing　the　fault　characteristicsit　is　found　that　the　fault　current　on　both-end　lines　when　internal　fault　occurs　is　no　obvious　linear　relationship,whereras　the　fault　current　on　both-end　lines　when　external　fault　occurs　is　obvious　linear　relationship.　According　to　the　difference　of　current　fault　characteristics　on　the　double-end　lines　when　internal　or　fault　occurs,　a　pilot　protection　method　for　hybrid　DC　transmission　lines　based　on　correlation　coefficient　is　proposed　in　this　paper.　The　simulation　model　of　LCC-MMC　hybrid　double-ended　DC　transmission　line　was　built　by　PSCAD,　which　is　used　to　output　the　fault　data　under　different　conditions.　And　the　fault　data　processed　with　MATLAB　to　carry　out　the　algorithm　simulation.The　simulation　results　verify　the　correctness　of　the　proposed　protection　method.　In　the　practical　application,　the　proposed　method　does　not　need　the　fault　data　on　both　ends　to　be　strictly　synchronized,and　it　can　identify　the　fault　quickly　and　reliably　with　strong　practicability.　©　2019　IEEE.