The aim of this research was to evaluate the coral reef condition in Sempu's strait. This research has beeb conducted at December 2017 used PIT method in four research stations i.e. Teluk Semut 1, Teluk Semut 2, Watu Meja and Fish Apartement. In generally the substrate of Sempu strait was devided into two categories, they were living and non-living substrate. Living substrate include HC, SC, NIA, SP and OT while non-living were RKC, RC, RB, SD and SI. Station 1 was dominated by hard coral (33.75%), station 2 and 3 was by rock (59.38% and 40.63%), and station 4 was dominated by sand (39.38%) respectively. Based on the monitoring, the coral reefs ecosystem of Sempu Strait was categorised in damaged condition. It could be seen by the high covering of dead coral and the low covering of healthy coral along observed stations. The coral reefs rehabilitation program is needed to recover the reefs ecosystem in Sempu Strait.