A　one-dimensional　model　is　proposed　for　sound　absorption　of　a　porous　metal　plate　with　finite　thickness　at　high　sound　pressure　levels　(SPLs),　where　the　sound　pressure　is　linear　with　the　particle　velocity　at　the　back　of　the　plate.　In　order　to　predict　nonlinear　acoustic　performance,　the　particle　velocity　inside　the　porous　plate　is　solved　by　a　linearization　and　finite　difference　method.　Acoustic　measurement　for　two　porous　metal　plates　was　performed　in　an　impedance　tube;　the　normal　surface　impedance　and　sound　absorption　coefficient　at　different　SPLs　were　obtained.　Good　agreement　between　the　experimental　and　theoretical　results　validates　this　model.　The　method　developed　here　can　be　also　applied　to　other　rigid　porous　materials.