Abstract: The performance characteristics of sandwich plate-style thermal shroud are briefly described,and the reliability problems such as pressure-resistant ability and air tightness are put forward.Based on the test analysis of the sandwich structure test plates with different welding and shaping methods,it is confirmed that stainless steel plates with different welding methods will suffer damage to varying degree,and then the pressure-resistant ability of the sandwich structure test plates will be affected.Among the three welding methods,resistance welding is the best way,next are the laser welding and argon-arc welding.Anyhow,welding parameters should be adjusted and optimized during the welding process.For the sandwich structure test plate welded with the optimized resistance welding parameters,it's bursting pressure under hydraulic bursting test can approach the actual fracture strength of the base metal.The analysis shows that the thickness of the plate,the size of welding spot and matrix point spacing will significantly affect the pressure resistance and safe expansion height of the sandwich structure test plate.Parameters like thickness of the plate,diameter of welding spot,and matrix point spacing are recommended as 0.5~2.5 mm,2~16 mm and 50~100 mm respectively.The safe expansion height within these parameters is more than 10 mm.The actual pressure-resistant ability of thermal shroud processed by different welding methods is suggested to be verified by welding test plates.The matrix integrity of welding spots cannot be assured because of various openings including the position for the inlet and outlet distribution tube,and the position for the edge sealing,therefore,some welding spots should be supplemented.