Molten　salt　corrosion　behavior　plays　an　important　role　in　the　safe　operation　of　molten　salt　thermal　energy　storage　system.　In　this　work,　the　dynamic　corrosion　behavior　of　347H　stainless　steel　are　investigated　in　quaternary　nitrate-nitrite　molten　salt　(QNN-MS)　and　its　nanofluids.　The　results　show　that　obvious　scouring　gullies　were　observed　on　the　surface　of　the　347H　coupons　in　dynamic　QNN-MS　compared　with　the　static　condition.　The　mass　loss　(m　mass　)　of　347H　after　1000h　in　QNN-MS　with　flow　rates　of　2　m/s,　1.3　m/s,　and　0.6　m/s　were　2.54　mg/cm2,　2.32　mg/cm2,　and　2.07　mg/cm2,　respectively,　which　were　about　88.15%,　71.51　%　and　53.33%　higher　than　that　under　static　condition.　After　adding　SiO2　nanoparticles,　the　corrosiveness　of　QNN-MS　to　347H　metal　was　reduced.　At　flow　rates　of　2　m/s　and　0　m/s,　the　m　mass　of　347H　after　1000　h　of　corrosion　in　QNN-MS　based　nanofluids　decreased　by　0.70　mg/cm2　and　1.36　mg/cm2　compared　to　that　in　QNN-MS,　respectively.　Meanwhile,　the　dynamic　corrosion　mechanism　is　comparatively　discussed　by　SEM,　XRD　and　EDS　method.　This　work　could　provide　basic　corrosion　data　for　the　design　and　optimization　of　molten　salt　thermal　energy　storage　system.