Reflectance spectra of eight common scleractinian coral species were chosed to represent the reflectance of corals in the sea area of Luhuitou, Sanya Bay in the north-western South China Sea (SCS). Reflectance spectra of these scleractinian corals, Padina Pavonicaand coral sand were measured using a fiber spectrometer. Then spectral reflectance analysis and derivative spectroscopy were used to study the diference of the reflectance spectrum of reef building scleractinian coral, Padina Pavonica and coral sand in this sea area. The results showed that reflectance difference of Padina Pavonica and scleractinian coral is very significant in 500～700 nm; reflectance of coral sand is significantly higher than that of coral reflectance spectrum with significant differences. Derivative analysis results showed that the distinguishable bands of scleractinian coral, Padina Pavonica and coral sand are as follows: scleractinian coral and Padina Pavonica, first order derivatives are mainly in 415.1～425.6, 482～487, 514.5～529, 577～587.6 and 631.9～644 nm bands. The second order derivatives are mainly in 413～418.7, 427.4～432.5, 462.3～470.6, 494.4～503.6, 551.6～561.4, 590～594 and 639～643 nm bands. The fourth order derivatives are mainly in 412.2～418.4, 420.5～425.3, 470.9～480.2, 481.3～486.9, 540.8～545.7, 560～568.3 and 635.6～639.6 nm bands. First order derivatives of scleractinian coral and coral sand are mainly in 400～413.7, 514.5～529.6, 576.9～587.6 and 602.7～667 nm bands. The second order derivatives are mainly in 420.5～430.7, 446.9～458.8, 467.3～472.3, 537～544.3, 556.8～561.4, 582.8～587.2 and 637.6～649.4 nm. The fourth order derivatives are mainly in 414.4～418.7, 419.5～430.3, 486.9～495.8, 534.2～540.1, 579～583.1, 622.7～627.5, 640～645 and 665.4～672.8 nm bands.