A　measurement　system　is　established　for　the　parabolic　trough　unit　mirror　in　concentrating　solar　power　(CSP).　The　system　applies　the　fringe　reflection　technique　and　the　temporal　phase　unwrapping　technique.　Based　on　three-dimensional　profilometry　system　model,　the　measurement　system　has　less　equipments　and　simpler　operation.　Without　any　strict　requirements　to　the　system　equipment,　a　sinusoidal　fringe　is　projected　with　projector,　and　the　images　are　recorded　by　a　camera　after　reflected　by　the　unit　mirror.　Then　the　surface　is　computed　by　the　parameters　of　the　system.　Experimental　results　verify　that　the　measurement　method　is　reliable.　The　system　is　helpful　to　the　measurement　work,　and　has　a　very　good　application　prospect　in　the　solar　thermal　power　field.