Abstract: Based on the experiments for the influences of temperature,grain size,time,etc.on the balance moisture,the causes of the influences of various factors on the balance moisture content are analyzed,and on the basis of testing a lot of samples,the technical parameters of determination method of balance moisture are modified and improved,the optimal conditions of experiment are detemined,providing the accurate and reliable guarantee for the isothermal adsorption experiment.The corresponding test parameters and error range are presented.