To　study　on　the　mechanical　behaviors　of　steel　H-pile　of　integral　abutment　jointless　bridges(IAJBs)　at　the　ambient　temperature　or　on　earthquake,　reciprocating　low-cycle　pseudo-static　tests　on　soil-steel　H-pile　interaction　were　carried　out　under　balanced　and　unbalanced　earth　pressure,　respectively.　The　soil　resistance,　the　strain　and　the　bending　moment　of　the　steel　H-piles　were　comparatively　analyzed.　The　results　indicate　that　the　unbalanced　soil　pressure　has　a　significant　influence　on　the　mechanical　behavior　of　the　pile　foundation　under　positive　loadings,　but　a　less　influence　under　negative　loadings.　The　soil　resistance,　the　strain　and　the　bending　moment　of　the　piles　for　abutment-steel　H-pile(AHP)　specimen　and　the　steel　H-pile　with　the　unbalanced　earth　pressure　of　backfill　behind　abutment(UHP)　under　positive　loadings　are　larger　than　those　under　negative　loadings.　However,　the　soil　resistance,　the　strain　and　the　bending　moment　of　the　piles　for　steel　H-pile　considering　the　balanced　earth　pressure(HP)　are　basically　the　same　under　positive　and　negative　loadings.　The　soil　resistance,　the　strain　and　the　bending　moment　of　the　piles　for　AHP　specimen　are　largest,　followed　by　those　of　the　UHP　specimen,　and　those　of　the　HP　specimen　are　minimum.　Therefore,　AHP　specimen　enter　the　elastic-plastic　state　fastest.　©　2021,　Editorial　Department　of　Journal　of　Southeast　University.　All　right　reserved.