Abstract: Microbialites with microcolumnar growth morphology occuring on the surfaces of crypts of coral reef were first found in beachrock on Shuiwei ridge, Luhuitou Peninsula.This kind of microbialites is a special one and different from microbialites found in beachrock on Heron Island by Webb et al(1999).The growth pattern of microbialites was discussed and divided into 5 growth phases. The discovery of the microbialites in the beachrock suggests a clear microbial origin for certain carbonate cements. Three types of the endolithic microbial borings were preserved in the coral reefs and seashells of the beachrock. Seashells collected from Shuiwei ridge beachrock containing microborings appear to have preserved most of their original fibrous and prismatic shell texture. Microborings in beachrock can be interpreted as microbial tracks and indicate that microbial play an important role during the forming of the beachrock.