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 similar to 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 similar to 425. 6, 482 similar to 487, 514. 5 similar to 529, 577 similar to 587. 6 and 631. 9 similar to 644 nm bands. The second order derivatives are mainly in 413 similar to 418. 7, 427. 4 similar to 432. 5, 462. 3 similar to 470. 6, 494. 4 similar to 503. 6, 551. 6 similar to 561. 4, 590 similar to 594 and 639 similar to 643 nm bands. The fourth order derivatives are mainly in 412. 2 similar to 418. 4, 420. 5 similar to 425. 3, 470. 9 similar to 480.2, 481. 3 similar to 486. 9, 540. 8 similar to 545. 7, 560 similar to 568. 3 and 635. 6 similar to 639. 6 nm bands. First order derivatives of scleractinian coral and coral sand are mainly in 400 similar to 413. 7, 514. 5 similar to 529. 6, 576. 9 similar to 587. 6 and 602. 7 similar to 667 nm bands. The second order derivatives are mainly in 420. 5 similar to 430. 7, 446. 9 similar to 458. 8, 467. 3 similar to 472. 3, 537 similar to 544. 3, 556. 8 similar to 561. 4, 582. 8 similar to 587. 2 and 637. 6 similar to 649. 4 nm. The fourth order derivatives are mainly in 414.4 similar to 418. 7, 419. 5 similar to 430. 3, 486. 9 similar to 495. 8, 534. 2 similar to 540. 1, 579 similar to 583. 1, 622. 7 similar to 627. 5, 640 similar to 645 and 665. 4 similar to 672. 8 nm bands.