Abstract: Based on existing data, the effect of single factor environmental change on the growth of hematypic coral was investigated. The growth of coral reef is controlled by sea-level so as to form its functional skeleton adaptable to eustatic sea-level fluctuations. Rise in atmospheric CO2 level can decrease the CO3^2- concentration in seawater and reduce the saturabilities of CaCO3 minerals(mainly the aragonite and calcite), thus slowing the calcification process of hematypic coral and threatening seriously the oceanic environment where the ecological system of growing hematypic coral relies on. The high ratio of x(Mg) to x(Ca) of aragonite sea in the Late Paleozoic was disadvantageous to the growth of low-magnesian calcite rugose coral but, on the contrary, advantageous to the modern aragonite hexacoral. Water eutrophication can easily induce the symbiodic algae to go out of coral polyp host and make the coral albinistic even dead.