The invention discloses a double-layer air-guide heat insulation shield of a polysilicon hydriding furnace, which comprises an inner-layer heat insulation shield and an outer-layer heat insulation shield sleeved outside the inner-layer heat insulation shield, wherein heat insulation chassises are arranged at the bottom of the inner-layer heat insulation shield and the bottom of the outer-layer heat insulation shield, and an air-guide channel is formed between the inner-layer heat insulation shield and the outer-layer heat insulation shield; an air
inlet channel is arranged at the lower part of the outer-layer heat insulation shield, and an air
inlet channel is arranged at the upper part of the inner-layer heat insulation shield. In the invention, two
layers of heat insulation shields are arranged, and the air-guide channel is formed between the two heat insulation shields, therefore, process
tail gas can enter into a reaction region in the inner-layer heat insulation shield through the air-guide channel. The invention has the advantages: firstly, the process
tail gas is poor conductor of heat and can play a better heat insulation role; secondly, the process
tail gas is preheated after absorbing heat transferred from the reaction region while passing the air-guide channel, thereby improving the reaction efficiency of the process tail gas after entering into the reaction region; and thirdly, the
airflow direction formed by the double-layer heat insulation shield can ensure that the device is
safer and more stable.