Abstract: Systematic investigations of scleractinian corals in the natural environment are relatively lacking since the global decline of coral reefs. In this study, we selected three corals with typical morphology from Sanya, including Pocillopora damicornis, Porites lutea and Pavona decussata. We investigated the symbiodinium density, chlorophyll-a content and effective quantum yield (Φ _PSII) for one year. The results show that: ① There are significant interspecific differences among the three corals. The scleractinian density and chlorophyll-a content of P. lutea are the highest, while the Φ _PSII is the lowest. ② About symbiodinium density, the lowest value of P. damicornis appeared in winter, while the lowest value of P. damicornis and P. decussata appeared in spring. The chlorophyll-a content and Φ _PSII of the three corals show similar pattern of seasonal changes, higher in autumn and winter, lower in spring and summer. ③ The photosynthetic characteristics of corals are related closely to the ecological health of coral reefs, and have clear interspecific differences and seasonal differences. Therefore, the interspecific differences and environmental dynamic changes of scleractinian corals, as an important indicator, need serious consideration in the coral reef monitoring and health assessment.