Soil salt transformation plays an important role in the freeze-thawing process，which is also one of basic problems of cryopedology． The very special law is made up of the two time salt-moisture transfer under freeze-thawing condition． Based on the latest research at home and abroad，through the investigation of soil moisture-salt change in the freeze-thawing process，the conclusion is made that the soil water potential gradient is the main driving force of soil salt movement and the factors are of quantities． The research shows that，when freezing，temperature drops，salt and moisture move towards frozen layer． All make the salinity content of the frozen layer increase significantly． In the thawing process，salinity and moisture in the soil move up again with evaporation and makes the salt second migration．