Damage to coral reef ecosystems is a major problem on the islands of Gili Air and Gili Trawangan. This will have an impact on the presence of reef fish in the area. This study aims to look how much relation caused by associated between live coral cover and reef fish in Gili Air and Gili Trawangan island.. This research method using Line Intersept Transect (LIT), Underwater Visual Census and simple linear regression analysis to know the relation. The percentage of coral cover on Gili Air Island and Gili Trawangan Island on reef flats (1-5 m) is 11.75% and 11.67% respectively, on the reef slopes (6-10 m) the percentage is 50.4% and 48.9%. In addition we observed the existence of 11 families reef fish. The abundance of reef fish on Gili Air and Gili Trawangan islands on reefs flat with an average of 0,406 ind / m2 and 0,137 ind / m2, on the reef slope on average - respectively 0,434 ind / m2 and 0,274 ind / m2. The determinant value in Southern part of both island indicates a value close to +1 and in Northern part of both island indicates a value close to -1.