Lots of studies on the microbial mat from the modern examples to the rock records show that the microbial mat is actually a complex microbial community. Just like a complex food web, microbial mats are communities of microorganisms in which each member depends and is depended on by others in the community. Importantly, this special microbial community forms abundant and sophisticated records in sedimentary rocks. For these records, the stromatolite is the typical represent of microbial mats in carbonate rocks, and the MISS (Microbial induced sedimentary structure) is the representative product that is related to microbial mats in siliclastic rocks. Longterm researches on these special records result in a young branch of sedimentology, i.e. “microbial-mat sedimentology” within the framework of geobiology, which plays a key role in the further studies of the evolution of the early life and in the further understanding of the evolutional rules of both the atmosphere and the hydrosphere in the earth. Lots of new concepts and thoughts have provided  this young branch of sedimentology with the powerful vitality, which marks an important advancement of sedimentology.