In　order　to　achieve　the　two-dimensional　(2-D)　velocity　measurement　of　a　flow　field　at　extreme　condition,　a　2-D　interferometric　Rayleigh　scattering　(IRS)　velocimetry　using　a　multibeam　probe　laser　was　developed.　The　method　using　a　multibeam　probe　laser　can　record　the　reference　interference　signal　and　the　flow　interference　signal　simultaneously.　What　is　more,　this　method　can　solve　the　problem　of　signal　overlap　using　the　laser　sheet　detection　method.　The　2-D　IRS　measurement　system　was　set　up　with　a　multibeam　probe　laser,　aspherical　lens　collection　optics,　and　a　solid　Fabry-Perot　etalon.　A　multibeam　probe　laser　with　0.5-mm　intervals　was　formed　by　collimating　a　laser　sheet　passing　through　a　cylindrical　microlens　arrays.　The　aspherical　lens　was　used　to　enhance　the　intensity　of　the　Rayleigh　scattering　signal.　The　2-D　velocity　field　results　of　a　Mach　1.5　air　flow　were　obtained.　The　velocity　in　the　flow　center　is　about　450　m/s.　The　reconstructed　results　fit　well　with　the　characteristic　of　flow,　which　indicate　the　validity　of　this　technique.　(c)　The　Authors.