The invention discloses a hot air supply device for a quick deicing and snow removing system at the bottom of a high-speed rail train. The hot air supply device comprises air supply columns arranged on one side of a deicing and snow removing station of the train, the air supply columns are lined up on the ground and evenly arranged, and 11-13 air supply columns are arranged corresponding to each section of train body. The air supply columns are fixed to the ground, communicated with an underground civil engineering delivery conduit and connected with a hot air unit in a hot air machine room through the underground civil engineering delivery conduit. Each air supply column of the hot air supply device comprises a column body, an air supply port, an air supply angle four-way regulating and locking device and an air quantity regulating valve, the air supply port is arranged on the top of the air supply column, and the air supply angle four-way regulating and locking device is arranged in the air supply port. According to the hot air supply device, hot air at a certain speed is blown out towards the bottom of the train through the air supply columns, heat exchange between ice and snow and the train body can be enhanced and the overall environment temperature of a garage can be improved through the air supply temperature and flowing of the hot air, and the functions of quick deicing and snow removing can be achieved. According to the hot air supply device, it can be guaranteed that the longest deicing operating time at the bottom of the compartment of the train is less than one hour, and technological requirements can be met.