The present paper has described macroscopic and microscopic textures of Dinosaur egg crust fossils. Under microscope and SEM, some tissues and textures of Dinosaur egg crust were observed, such as relic egg crust membrane fabrics, conical layers and prismatic layers. Carbon and oxygen isotopic analysis of Dinosaur egg crust fossil was made, which led to the discovery that carbon isotopes of Dinosaur egg crust fossils are composed of three parts. There exists organic carbon in primary carbonate minerals, secondary carbonate minerals formed in the diagenetic process and organic matter closely related to Dinosaurs; nevertheless, carbon is mainly of inorganic origin.δ13C anomalies are mainly related to diagenetic secondary change. Oxygen isotopes mainly reflect oxygen isotopic composition of underground fluids in the diagenetic process, but have little to do with primary oxygen isotopic composition of Dinosaur egg crust. The richer the heavy oxygen in Dinosaur egg curst fossils, the less these fossils suffered from diagenetic secondary change. Compared with Dinosaur egg crust fossils from Nanxiong Basin, the Dinosaur eggs in Xixia basin experienced much stronger diagenesis. Therefore, if one wants to trace the food type, ecological environment and extinction of Dinosaurs in the light of carbon and oxygen isotopic values of Dinosaur egg crust fossils, he must separate primary carbonate minerals of Dinosaur egg crust fossils from their secondary carbonate minerals and, what is more, isolate organic matter to make carbon and oxygen isotopic studies.