By the study of different kinds of dinosaur footprint fossils found in the dark mudstones and oil shales of the Xiguayuan Formation(Upper Jurassic-Lower Cretaceous)  in Luanping Basin and the lithofacies characteristics of the dark mudstones and oil shales，the sedimentary environment of the dinosaur footprint fossils was analyzed. The dark mudstones  with dinosaur footprint fossils were deposited in semideep lake or front fan delta environments which indicated that the lake level changed frequently. During the dry season，the lake level fell，and the dark mudstones in deep lakesemideep lake facies exposed to the air. Some dinosaurs went to the lower part of the basin to drink water，and their footprints were left in the dark mudstones. Consequently, it is concluded that all the sandstone conglomerates interlayered in the dark mudstones and the salt rocks in the Paleogene continental faulted basins in eastern China are not formed by deep water gravity flow. The sedimentary models of the sandstone conglomerates and salt rocks interlayered in dark mudstones were established to show their origins.