Aiming　at　measuring　tree　barriers　in　transmission　line　corridors,　a　binocular　vision　ranging　method　is　proposed　to　measure　the　distance　between　the　transmission　lines　and　trees.　Based　on　the　principle　of　binocular　vision　ranging,　the　binocular　camera　is　calibrated　using　a　marked　checkerboard　as　a　calibration　board.　Then,　the　SAD　region　matching　algorithm　is　applied　to　the　preprocessed　images,　and　the　disparity　map　is　acquired.　Finally,　the　distance　between　the　tree　and　the　transmission　line　can　obtain　according　to　the　three-dimensional　coordinate　information　of　two　target　points.　The　results　of　the　experiments　show　that　the　proposed　binocular　vision-based　method　can　achieve　the　measurement　error　within　±30cm.　The　precision　can　meet　the　need　of　measuring　the　distance　between　trees　and　the　transmission　lines,　which　is　an　effective　way　for　warning　tree　barriers　in　transmission　line　corridors.　©　2018　IEEE.