The process of soil freezing and thawing has an important influence on the evolution of climate and ecological environment. In order to study the soil freezing and thawing process and its response to climate change in the seasonal frozen soil region,the daily variation of soil freezing and thawing process and its relationship with air temperature and soil temperature were analyzed based on the observation data of frozen soil,air temperature and soil temperature of the four typical representative stations from 2014 to 2017 in Jilin Province. The results showed that the upper limit of frozen soil showed a linear upward trend,and the lower limit value showed a trend of three times curve in the whole process of soil freezing and thawing. From the beginning of stable freezing,the lower limit of frozen soil increased gradually,and it decreased slowly after reached the maximum. The process of soil thawing include the lower and upper soil thawing. The upper limit of frozen soil have thawed at the same time or later than lower limit,but the daily variation of soil thawing of the upper limit was greater than the lower limit. During the soil freezing process,the accumulated air temperature,accumulated soil temperature at 0 cm, accumulated soil temperature at 10 cm and the depth of freezing had three times curve relationship,with the increase of negative accumulated temperature,the depth of freezing increased. The accumulated air temperature, accumulated soil temperature at 0 cm,accumulated soil temperature at 10 cm and the depth of upper limit of frozen soil had three times curve relationship in the process of upper limit of soil thawing,with the increase of positive accumulated temperature,the depth of upper limit of frozen soil increased. During the process of lower limit of soil thawing,the accumulated air temperature,accumulated soil temperature at 0 cm,accumulated soil temperature at 160 cm and the depth of lower limit of frozen soil showed a linear trend significantly. The depth of lower limit of frozen soil decreased with the increase of positive accumulated air temperature,the depth of frozen soil was shallower.