The　quantitative　research　on　swelling　properties　of　bentonite　considering　the　influence　of　salt　ions　under　the　effect　of　hydrothermo-mechanical　coupling　is　relatively　weak.　Based　on　a　calculation　model　for　the　swelling　characteristics　of　bentonite　from　a　fractal　perspective,　this　work　proposes　a　novel　coupled　multifield　control　equation　for　unsaturated　bentonite　considering　the　influence　of　salt　ions.　The　numericalization　of　the　coupling　control　equation　was　completed　by　secondary　development　of　a　numerical　analysis　platform.　The　new　theoretical　model＇s　dependability　and　validity　were　validated　by　comparing　it　to　experimental　data.　The　evolution　of　the　related-field　quantities　under　the　multifield　coupled　effect　in　salt-bearing　environments　was　obtained,　and　the　effect　of　salt　ion　concentration　was　analyzed.　The　calculation　showed　that　the　temperature　of　bentonite　changed　periodically　with　changing　ambient　temperature.　Temperature　gradient　induces　migratory　movement　of　water　from　high　to　low　temperature　regions.　The　hollow　axisymmetric　soil　sample　gradually　saturated　from　outside　to　inside　with　increasing　water　injection　rate　at　the　outer　cylindrical　surface.　The　swelling　pressure　of　bentonite　will　increase　with　an　increase　in　water　content,　whereas　the　presence　of　salt　ions　weakened　the　swelling　behavior.　Temperature　and　relative　humidity　were　less　affected　by　salt　ion　concentration.