On　the　basis　of　the　analysis　for　collected　speed　data　on　representative　road　sections　of　Qinghai-Tibet　Highway　under　different　altitudes,　the　operating　speed　and　variational　rules　in　tangent,　sharp　curve　and　longitudinal　gradient　sections　of　Qinghai-Tibet　Highway　were　proposed　respectively　by　using　free　flow　speed　cumulative　curve　of　different　vehicle　types.　Meanwhile,　the　influences　of　altitude　on　operating　speed　were　discussed.　Results　show　that　the　vehicle　can　reach　the　desired　speed　on　straight　flat　sections　without　road-side　interruption　and　the　operating　speed　rapidly　changes　on　the　sharp　curve　section.　Altitude　at　4　km　is　the　threshold　which　has　great　influence　on　operating　speed.　Compared　with　lower　altitude,　the　influence　of　longitudinal　gradient　at　altitude　over　4　km　on　operating　speed　of　upgrade　direction　is　larger.　The　conclusions　of　typical　operating　speed　characteristics　of　Qinghai-Tibet　Highway　can　establish　a　foundation　of　operating　speed　design　method　and　highway　safety　evaluation.