Abstract: The electrochemical corrosion property of weld metal of the austenitic stainless steel SUS316 in TIG welding, MIG welding and TIG welding with welding wire(TIG +M)were tested with PASTAT30 type potentiostat.The results show that corrosion resistance of weld metal in TIG welding is the least compared with base metal and welded metal in MIG welding and TIG welding with H0Cr19Ni12Mo3 welding wire not only in 5% HCl but also in 9.8% H2 SO4.And the order of electrochemical corrosion resistance in 9.8% H₂SO₄ is base metal, welded metal in TIG +M, MIG welding and TIG welding.The order in 5% HCl is base metal, welded metal inMIG welding, TIG+M and TIG welding.Passivation zone in H₂SO₄ is more length than which in HCl, so corrosion resistance of the austenitic stainless steel in H₂SO₄ is better than which in HCl.Huey test was also carried out, and the result of this test was coincident with the result of the electuochemical corrosion test in 9.8% H₂SO₄.