Cambrian Gushan Formation, belonging to the upper part of Series 3, is made up a general upward shallowing succession of sedimentary facies from shelf marls to grain-bank oolitic grainstones. Within one bed of the grain-bank oolitic grainstones in the upper part of Gushan Formation, occur many dome-shaped carbonate structures with the distribution like a string of beads that can be described as the stromatolitic bioherm. Since stromatolites are typical buildups of microbial mats, these stromatolitic bioherms with special macro-and microscopic fabrics can further be grouped into the microbial reef, and become the typical example for the further understanding of both the sedimentation pattern in the shallow skeleton-poor sea before the biological radiation of the Middle Ordovician and the microbial reef-building features in this special geological time.