Shore-shallow lacustrine beach-bar sandbodies widely developed during the period of the upper submember of the fourth Member of the Shahejie Formation of Paleogene in the Western Dongying Depression. The environmentally sensitive grain size components of beach-bar sandbodies have been studied using the method of grain size-standard deviation according to the description of cores and other correlated analyses and tests. Combined with the analysis of grain size probability curves and the research of palaeotopography and palaeocurrent, four kinds of environmentally sensitive grain size components were determined in the study area, which respectively represents suspension transportation, coastal current, wave and storm wave or gravity flow.