Abstract: The decrease of clay content will weaken the erosion resistance of the soil and bring some influences on the dispersivity tests. For the low liquid limit clay, field investigation and mineral and chemical composition analysis show that the soil material does not have the characteristics of dispersive soil. The double-hydrometer tests, crumb testss, pinhole tests, pore water solution tests and exchangeable sodium ion percentage tests are used to carry out nearly 100 groups of experimental researches. Among them, the results of the double-hydrometer tests are relatively scattered, so it is difficult to give the identification conclusions and it is for reference only. Because of the poor erosion resistance of soil samples, the pinhole tests are difficult to be successfully completed. Both the soil block tests and the pore water solution tests are mainly non-dispersive soil, and a small amount of transitional soil. The percentage of exchangeable sodium ion tests are all non-dispersive soil. The soil material is identified as non-dispersive soil. In addition, the reasons are analysed why the double-hydrometer tests and pinhole tests have not achieved reasonable results, and it is regarded out that the two methods are not suitable for this kind of soil.