Based　on　MATLAB　program　and　by　implementing　the　distributed　parameter　method,　the　2-D　model　of　reverse-flow　plate　fin　heat　exchanger(PFHE)　was　constructed.　The　numerical　results　were　compared　with　the　experimental　results　in　a　multi-stream　PFHE　used　in　liquefier　in　Claude　cycle,　and　the　numerical　results　were　in　good　agreement　with　the　experimental　results.　The　effect　of　the　axial　conduction　on　heat　transfer　performance　of　PFHE　was　investigated,　and　it　was　observed　that　the　effectiveness　of　PFHE　considering　axial　conduction　decreased　by　21.8%,　compared　with　that　without　considering　axial　conduction.　Moreover,　the　influence　of　the　adiabatic　boundary　condition　on　the　cold　and　hot　ends　of　separating　plate　of　PFHE　was　transferred　to　the　inner　domain　of　PFHE　by　axial　conduction　effect,　which　resulted　in　the　fluid　temperature　distortion　in　near-inlet　domain.　When　the　boundary　conditions　of　constant　wall　temperature　or　constant　heat　flux　were　adopted　on　hot　and　cold　ends　of　separating　plate　respectively,　the　fluid　temperature　distortion　in　near-inlet　domain　almost　disappeared.　When　considering　axial　heat　conduction,　compared　with　the　adiabatic　boundary　conditions　at　both　ends　of　the　partition,　the　effectiveness　of　the　constant　wall　temperature　boundary　conditions　increases　by　35.8%(Ε_c)　and　31.7%(Ε_h),　and　the　effectiveness　of　the　constant　heat　flow　boundary　conditions　increases　by　22.8%(Ε).　©　2021,　Editorial　Board　of　CIESC　Journal.　All　right　reserved.