Speed　limit　sign,　speed　camera,　transverse　pavement　markings　were　widely　used　on　expressway　as　speed　control　devices　in　China.　Based　on　overall　analysis　of　accident　data,　the　changes　of　operating　speed,　standard　deviation　and　vehicle　proportion　of　speed　deviation　range　in　20　km　·　h-1　pace　of　three　kinds　of　speed　control　devices　were　compared.　The　statistical　significant　tests　were　conducted　to　evaluate　the　influence　of　speed　limit　sign,　speed　camera　and　transverse　pavement　markings　on　operating　speed.　Results　show　that　speed　camera　has　greater　effect　on　speed　limit　than　others.　The　speed　limit　sign　combined　with　road　warning　sign　has　greater　effect　on　speed　limit　than　the　speed　limit　sign.　Anyway,　there　are　no　influences　on　the　operating　speed　while　it　is　far　from　locations　of　the　devices.