Cretaceous Bashijiqike formation in Kuqa depression, was selected as study layer. The dissolution of quartz grain in sandstone reservoirs were abroad. And the dissolution of interior and rim of quartz grain was the major characteristics of dissolution. There were clear lateral differentiation in dissolution values of quartz grain. What’s more, it were abundant of analcime cements and illite, but were deficient of kaolinite in the reservoir where high dissolution values of quartz grain. Salinity of syndepositional water body was acquired based on mensuration of content of “B” in mudstone interbedded sandstone. It was noteworthy that the lateral distribution rules of salinity of syndepositional water body were similar to that of dissolution values of quartz grain, which makes clear that distribution rules of salinity of syndepositional water body were the major controlling factors for differentiation of dissolution of quartz grain.