Abstract: The soil-water characteristic curve is one of the important curves describing unsaturated soil characteristics, measuring the curve precisely is one of the key to unsaturated soil mechanics. The influential factors and abnormal phenomenon in the test using GCTS-type soil-water characteristic curve(SWCC)device are investigated. The results show:(1)because the dry climate in lanzhou and long test time, the water loss caused by evaporation is dominant with the increasing of time, which affects the test results seriously. The evaporation for the instrument in Lanzhou city all the year round has been calibrated, which could be used to correct measurement results.(2)the ceramic plate is the core component of the instrument, directly affects the test time and test results, 5bar ceramic plate matches matrix suction of loess and shorten the test time; (3)the drying test could avoid pressure difference caused by the instrument structure, thus reduced experimental error. Based on the above conclusion, some suggestions and improving methods for SWCC test proposed.