Defrosting system of low-temperature freezer

The utility model relates to the field of refrigeration defrosting, in particular to a low-temperature freezer defrosting system, which comprises a water pan and a double-pipe drain pipe, the drain pipe comprises a main pipe and an auxiliary pipe, one end of the main pipe is communicated with the water pan, the other end of the main pipe leads to the outside of a freezer, hot fluid is connected into the auxiliary pipe, and the auxiliary pipe is contacted with the main pipe, so that the main pipe cannot be frozen and blocked. The drain pipe adopts double pipes, and hot fluid generated in the operation process of a refrigeration system of the freezer is introduced into the auxiliary pipe, so that the auxiliary pipe is in contact with the main pipe, and the main pipe cannot be frozen and blocked. On one hand, the existing hot fluid of the refrigerating system is utilized, the heating effect is good, the use cost is low, and the drainage pipe can be always heated as long as the refrigerating system runs, and on t