The invention provides an in-situ monitoring soil freeze-thawing device and a method for testing the 
soil carbon loss on the basis of the device, and aims at solving the problems that the existing wild method can only be used for monitoring the carbon 
discharge flux of a whole soil ecological 
system and cannot be used for monitoring the contribution of a specific soil layer to the carbon 
discharge, and a soil freeze-thawing process cannot be really reflected by indoor freeze-thawing 
simulation experiments. The soil freeze-thawing device mainly comprises a 
temperature monitoring instrument, a 
soil column chamber, an air buffer chamber, a rubber sleeve and an air guide 
pipe. The method for testing the 
soil carbon loss comprises the following steps of charging in-situ soil columns of different soil 
layers into the 
soil column chamber of the freeze-thawing device; burying the soil columns into corresponding oil 
layers; in a freeze-thawing period, monitoring the 
discharge condition of gases CO2 and CH4, and comparing the soluble organic carbon DOC change condition of the corresponding soil layer before and after the freeze-thawing; further calculating the total 
carbon loss quantity of the freeze-thawing process. The in-situ monitoring soil freeze-thawing device and the method for testing the 
soil carbon loss have the advantages that the CO2 and CH4 discharge flux of different soil 
layers and the change angle of the DOC content in the freeze-thawing process are integrated to calculate the soil 
carbon loss degree; the precision is improved by 30 to 50 percent.