Using the the geological comprehensive study method of transportation system, the hydrocarbon accumulation system of Cretaceous in Junggar Basin was studied. The characteristics and the spatial distribution of transportation system of meshwork-carpet type hydrocarbon reservoir system were analyzed. The results show that three classes and nine types of conductor department styles are defined. Transportation system plays a key role in the process of making carpet and diffusion in storage layer.Reticular and complex transportation system control formation, classification and distribution of oil and gas reservoir.