Based on the data of surface radiation flux, surface energy flux, and soil temperature and moisture collected from the Ali-Ritu station from August 21, 2016, to August 21, 2017, the soil freeze-thaw process was divided into four stages: freezing, completely frozen, thawing, and completely thawed by using soil temperature data. The characteristics of soil temperature and humidity changes and surface water and heat exchange during a freeze–thaw cycle were analyzed. The results show that: (1) The daily temperature difference of soil temperature at 5 cm in the surface layer was obvious. The moisture changes were relatively small at depths of 30 cm and 50 cm, reflecting the relatively stable moisture status of the middle soil. (2) The sensible heat flux, latent heat flux, net radiation flux, and surface heat flux at each stage of soil freeze-thaw showed significant diurnal changes, with all fluxes peaking in the afternoon. The fluxes during the thawing and the completely thawed stages were larger, while the fluxes during the freezing and the completely frozen stages were smaller. (3) At different depths, soil temperature and moisture showed clear "V"-shaped and "U"-shaped seasonal variation patterns, respectively. Net radiation increased in summer and decreased in winter. In the freeze-thaw stage, the sensible heat flux dominated, the latent heat flux was small, and the Bowen ratio fluctuated greatly. In the non-freezing stage, latent heat flux dominated and the Bowen ratio was relatively small. (4) The energy closure rate approached 1 during the thawing and completely thawed stages, indicating a good balance of surface energy budget. During the freezing and completely frozen stages, the closure ratio fluctuated significantly due to changes in soil state, deviated far from 1, resulting in low energy closure ratio. Diurnal freeze-thaw cycles existed in the soil, with the energy closure ratio being higher during the day than at night.