Abstract: The paper carries out the sedimentological analysis on fluvial styles and divides the channel system into single channel and multiple channel (or composite channel) systems. Straight channel, meandering channel and braided channel belong to single channel system, while anastomosed channel and other distributive fluvial systems belong to multiple channel system. Thick point bar, channel thalweg-filling sediment and counter point bar are the parts of meandering fluvial facies. An upward-finning meandering channel sequence is mainly composed of several microfacies such as thalweg deposit, sand bar complexes and over-bank fines. The architecture of a braided channel sandbody is very complex, and various large scale bedforms are distributed crisscrossly, the sandbodies in the channel can be divided into mid-channel sand bar, mid-channel sand sheet and several non-framework microfacies. The anastomosed river may be composed of braided river, meandering river and straight river, in another word, the single channel of anastomosed river can be divided into bedload channel, mixed-load channel and suspended-load channel. Terminal fan, meandering river fan, braided river fan and even some subaerial delta systems can be summarized into the distributive fluvial system. In fact, in the distributive fluvial system, the nature of the river has changed and the channel has been transformed from a confined channel to an unconfined channel. The concept of the distributive fluvial system is too general and broad, across the boundaries of different systems. There are many limitations in precise characterization of fluvial microfacies due to the great differences among different fluvial sand bodies