Abstract:Abstract: Based on related contents of GB/T 8170-2008 Rules of rounding off for numerical values & expression and judgment of limiting values,the significant digits,rounding off numerical values and operation rules for forest products detection were investigated in this paper.The shortages of rounding off numerical values which was commonly used in the past were analyzed,while the rationalities of rounding off to the nearest whole number were discussed.Rounding off numerical values by rounding after calculated was advocated.Through this way,the procedure can be simplified and the accuracy of data and the work efficiency of detection can be improved.