To　investigate　the　strength　design　of　the　plate-fin　heat　exchanger　header　based　on　energy　criteria,　the　calculation　methods　of　plastic　load　based　on　Ratio　plastic　work　curvature　(RPWC)　criterion　and　Plastic　work　curvature　(PWC)　criterion　are　compared.　The　plastic　pressure　results　determined　by　both　criteria　for　the　header　indicate　that　large　deformation　effect　will　strengthen　the　structure.　The　comparison　of　the　plastic　pressure　results　for　the　header　with　five　opening　ratios　ranging　from　0.2　to　1.0,　indicates　that　PWC　zero　curvature　plastic　pressure　is　the　largest,　RPWC　plastic　pressure　is　the　second　largest,　and　PWC　engineering　plastic　pressure　is　the　smallest;　The　ratio　plastic　work　corresponding　to　the　RPWC　plastic　pressure　is　less　than　that　of　PWC　zero　curvature　plastic　pressure.　The　RPWC　criterion　with　strict　critical　plastic　index　is　more　conservative,　simpler　and　more　intuitive　than　PWC　zero　curvature　criterion,　and　is　thus　suitable　for　such　complex　structure　as　the　plate-fin　heat　exchanger　header　for　calculating　plastic　load,　while　PWC　engineering　plastic　load　suggested　can　be　used　as　the　conservative　approximation　of　plastic　load　for　engineering　design.