A detailed study of internal architecture and reefforming model of Honghua reefs has been conducted  by outcrop observation and microfacies analysis. The Honghua reefs consist of three depositional cycles: Reef A consisting of bioclastic micrite limestone and framestone， reef B consisting of bioclastic micrite limestone， bindstone， framestone and bioclastic limestone，and reef C consisting of bindstone， framestone and bioclastic limestone. Reefbuilding organisms are calcareous sponges， calcareous algae， bryozoans and hydrazoans. The organisms adhering to the reef are foraminifera， brachiopods， bivalves， gastropods and echinoderms. The evolution of organisms in an individual reef is from group of brachiopods， bivalves and foraminiferas to calcareous algae to group of calcareous sponges， calcareous algae， hydrazoans and bryozoans to bioclasts， and that of lithology is from bioclastic micrite limestone to bindstone to framestone to bioclastic limestone. Considering the good rounding and sorting  of bioclasts in bioclastic bank of reef B， and the cementation by micrite， it is concluded that the bioclasts were transported from the adjacent high energy bank and deposited in reef B flank where the energy is low. Reef A was formed in low energy environment. Reef B and reef C were deposited over the highland made up by reef A in high energy environments. The individual reef-forming model is that calcareous algae binds grains and makes the basement hard， and calcareous sponge and calcareous algae abundantly buildup on the basement and form the reef that can resist waves， then the reef forms a bioclastic bank when it dies and is destroyed by waves and tide.