The corrosion behavior of four typical Ni-based corrosion-resistant alloys in supercritical aqueous solution of Na3PO4, Na2SO4 and NaCl at 450 ℃/23 MPa was studied by using XRD, SEM, etc. After corrosion for 50 h, the surface of the alloys was covered with short rod-shaped and needle-shaped products mainly consisting of NiCr2O4，Cr2O3，NiO，Ni3(PO4)2，CrPO4 and Na3PO4. With the prolong of time, the thickness of the corrosion layers increased and the corrosion resistance was ranked as X-1#>X-2#>625>C-276