Based on China National Standard of Soil Engineering Classification ( GB/T 50145-2007) and the Unified Soil Classification System of American Society for Testing Materials ( ASTM D-2478) ，two kinds of soil laboratory engineering classification methods were discussed and analyzed from the aspects of the definition in particle fraction，classification of soil type and evaluation standard for soil gradation． There is a same limit of fine grains fraction in the two standards，and there are three main types of soil in GB/T 50145-2007 and two in ASTM D-2487． Different evaluation standards of gradation are put forward for gravels and sands in ASTM D- 2487． Same criteria of A line，B line and controlling value of plastic index are in the plasticity chart of both standards．