Abstract: A high-speed flow liquid metal corrosion test device was designed and manufactured to study the corrosion behavior of 316 L stainless steel welds with different grades of sandpaper and different polishing treatments in the flow liquid lead-bismuth alloy at 550 ℃（ relative flow rate of 2. 62 m/s）. The studies found that all the samples formed a double oxide layer structure,the inner layer is mainly loose Fe₃O₄,and the outer layer is mainly dense Fe Cr₂O₄. The smaller the surface roughness,the slower the element mass transfer process. The smaller the abrasive effect of the high-speed liquid LBE,the better the corrosion resistance of the 316 L steel weld.