The invention discloses a dual sealing structure for an ultra high temperature double-layer 
water cooling quartz tube 
vacuum chamber. The dual sealing structure comprises a double-layer 
quartz tube nested structure, and stainless steel sealing assemblies respectively nested at two ends of the double-layer 
quartz tube nested structure; the double-layer quartz tube nested structure comprises an outer layer quartz tube and an 
internal layer quartz tube embedded in the outer layer quartz tube, and a ring-shaped cavity is formed between the outer layer quartz tube and the 
internal layer quartz tube; each stainless steel sealing 
assembly comprises a first stainless steel 
flange plate, a first stainless steel fastening circular ring, a second stainless steel 
flange plate and a second stainless steel fastening circular ring which are matched mutually, wherein a stainless steel cover is detachably mounted at the outer side of the second stainless steel 
flange plate; a 
water cooling port communicated with the ring-shaped cavity is formed in each stainless steel sealing 
assembly; a leaked 
water vapor vacuum isolation region is formed between the inner wall of each second stainless steel flange plate and the outer wall of the 
internal layer quartz tube, and the second stainless steel flange plate is provided with an exhaust tube communicated with the leaked 
water vapor vacuum isolation region. The dual sealing structure can achieve ultra high temperature, has excellent sealing property, and is safe and reliable.