The Lower Cretaceous in northern Himalayas mainly consists of clastic rocks. The submarine fans were well developed in this area. According to the minerals, textures,structures and occurrence of sedimentary rocks, the submarine fan can be divided into six subfacies. The subfacies and thier arrangements and combinations indicate various sedimentary environments. The evolution of the submarine fan can be divided into the embryo stage, young stage, peak stage, and the waning stage. The embryo and young stages were developed during the Early Age and Middle Age of the Early Cretaceous. The sand/mud ratio of sedimentary rocks are much higher than any of other stages. The sedimentary rocks are mainly sandstones with different minerals and textures. It means that the costal plain and shelf was very narrow and the sea floor was steep. The sedimentary environment was changed from shelf to slope. Major tectonic movements were extension, split and subsidence. During the Late Age of the Early Cretaceous, the submarine fans were in peak stage. Coastal plain and shelves were much wider than before. Sedimentary rocks were black shale and finegrained clastics with very large thickness. There are many siderite and calcic nodules and a few ammonite fossils in black shales. The ratio of sand/mud of sedimentary rocks is lower than any of other stages. The sedimentary facies changed slowly in this area. The sedimentary conditions belong to low energy, gentle slope without obvious slope breaks of continental margin. These characteristics indicate the significant marine transgression events in northern Himalayas.  As a result of the Indian Ocean spreading and the Indian Plate moving to the north during Early Cretaceous, the passive continental margin was well developed here. The sedimentary environment was transformed into bathyal and abyssal environments. Due to the marine regression, submarine fans evolved into waning stage in the Late Cretaceous and sedimentary rocks changed from shales to coarse sandstones even conglomerates. The sedimentary basins developed stage by stage from shelf to extension basin to slope, and at last to deep sea basin during the Cretaceous.