With global warming,the effects of freeze-thaw on soil properties have been increasingly emphasize. Taking saline and alkali soil in Shenzhou city of Hebei province as research object,the impacts of freeze-thaw on the physical and chemical properties of 020 cm deep saline and alkali soil were investigated by analyzing the changes of soil water content,water-holding capacity,bulk density,saturated hydraulic conductivity,electrical conductivity,pH and organic matter content.The results showed that freeze-thaw increased moisture content of the soil in 020 cm depth but had no apparent effect on water-holding capacity. For the 010 cm deep,freeze-thaw increased soil bulk density and pH,but reduced the electrical conductivity and permeability.The water and salt migration of the soil in this layer was special,the soil moisture content and conductivity showed the opposite trend.For the 1020 cm deep,freeze-thaw increased soil permeability and organic matter content.Soil bulk density was very significantly negatively correlated with the water-holding capacity(P <0.01),and significantly negatively correlated with soil moisture content(P < 0.05)in the 020 cm deep soil.The organic matter and saturated hydraulic conductivity had no significant correlation with other properties.The pH had very significant correlation with soil bulk density and moisture content,and it had significant correlation with water-holding capacity in the 010 cm deep soil.There were significant negative correlation between electrical conductivity and soil bulk density,and a significant positive correlation between electrical conductivity and water-holding capacity in 1020 cm deep soil.These results will provide a scientific basis for the study of the influence of freeze-thaw on saline-alkali soil and the improvement of saline-alkali soil.