It used to be considered that the Loushanguan Formation was composed of thick-bedded dolomite, which is very difficult for division. However, the authors discovered recently that the top and bottom surfaces of the Loushanguan Formation are palaeokarst unconformity interfaces, and there are a lot of interbeds of granular (oolite, pisolite and oncolite) dolomite and algae-mat dolomite, especially sedimentary structures such as the bird's eye, stromatolite, cross bedding and tepee structures. According to the characteristics of its vertical assemblage, the authors suggest that the Loushanguan Formation could be divided into three sections, and it is made of seven third-order sequences, the boundaries of which are palaeokarst unconformity interfaces or exposed zones. Each sequence is made of transgressive system tracts and highstand system tracts.