In order to establish simple and practical conversion methods for dry weight of Corbicula fluminea in Lake Datong, the relations among the three shell dimension parameters (length, width and height), dry and wet weight with shell, tissue dry weight and ash free dry weight were investigated. The regressions of tissue dry weight and ash free dry weight with the three shell dimension parameters fitted the formula y = axb. Among them, the percentage error (PE) between observed and predicted value of ash free dry weight obtained from shell width was low (24.6%). PE between observed and predicted value of tissue dry weight obtained from shell width and from shell length and shell height were varied from 29.7% to 40.5%. Tissue dry weight and ash free dry weight converted from wet weight with shell were more precise (the percentage error being 22.8% and 21.7%, respectively) than the other parameters. In conclusion, wet weight with shell could be directly converted to dry weight for Corbicula fuminea in Datong Lake using y = ax.