The invention discloses a 
crystalline silicon reduction furnace inner wall 
coating device and method. The 
crystalline silicon reduction furnace inner wall 
coating device comprises a base, a heating device, a 
gas exchange device and a power supply device, wherein the base is provided with at least two gas replacement holes; a hollow target material is the same as a 
bell jar in shape and smaller than the 
bell jar, the material of the target material is the same as the target material of a 
coating film, and the target material is arranged in the 
bell jar; the bell 
jar and the target material are positioned on the base; the bell 
jar is provided with a jacket, and a flowing medium with heat can be injected into the jacket; the heating device is arranged in the target material and is used for heating the target material; the 
gas exchange device is used for performing gas replacement on the space between the bell 
jar and the target material; when the target material is arranged in the bell jar, the gas replacement holes are positioned in a space between the target material and the bell jar; and the power supply device is provided with a positive 
electrode connected with the bell jar and a negative 
electrode connected with the target material. According to the 
crystalline silicon reduction furnace inner wall coating device, the ultrathin 
metal film with uniform structure and 
strong binding force can be prepared on the inner wall of a 
polycrystalline silicon reduction furnace, and each position of the inner wall of the bell jar can be coated at the same time, so that the problem of 
stress concentration or residue caused by segmented coating is solved.