The paper has summarized the Characteristics of the lithofacies of the stratum of the study area by measuring the Outcrops ,Sampling ,stone grinding and thin section microscopic analysis , simultaneously ,summarized the depositional environment of this area according to the Characteristics of lithofacies .After the study ,Changzhougou group in Xingcheng primarily represents tidal flat environment . Further ,the stratum of the study area is divided into 3 sections :Ⅰ section is mainly constituted by Medium-grained-Coarse-grained quartz sandstone ,representing supratidal zone depositional environment ;Ⅱ section is mainly constituted by Medium-grained-Fine-grained quartz sandstone and silty mudstone ,representing intertidal zone depositional environment ;Ⅲ section is mainly constituted by silty mudstone ,shale or mudstone ,representing subtidal zone depositional environment .