The　influence　of　initial　cracks　on　the　buckling　performance　of　square　steel　tubular　(SST)　columns,　widely　used　in　civil　engineering,　is　an　aspect　that　has　not　been　studied　in　detail.　Thus,　an　experimental　investigation　was　conducted　on　SST　columns　with　initial　crack　defects.　A　total　of　111　specimens　(12　single-crack,　48　double-crack,　48　three-crack,　and　3　no-crack　SST　columns)　were　tested　under　axial　compression　loading,　and　the　failure　modes,　initial　stiffness,　bearing　capacity,　ultimate　displacement,　and　strain　strength　of　each　specimen　were　reported.　Combined　with　the　experimental　data,　a　finite　element　analysis　of　the　validated　model　was　conducted　to　evaluate　the　effect　of　the　main　influencing　factors.　A　reduction　coefficient　was　obtained　via　statistical　analysis　and　introduced　into　the　prediction　formula　to　accurately　estimate　the　ultimate　bearing　capacity　of　multicracked　steel　tubes.　It　was　found　that　avoiding　crack　propagation　in　practical　engineering　is　crucial.　The　initial　cracks　accelerated　the　local　buckling　and　changed　the　bearing　and　deformation　capacities　of　the　SST　columns.　The　ultimate　loads　of　the　steel　tubes　increased　gradually　with　an　increase　in　the　tube　thickness　and　decreased　slightly　with　an　increase　in　the　crack　length.　Furthermore,　the　effect　of　crack　number　and　crack　spacing　on　the　bearing　capacity　was　found　to　be　complex,　and　there　was　a　coupling　relationship　with　the　tube　thickness;　therefore,　the　tube　thickness　of　the　component　should　be　reasonably　selected,　or　appropriate　anti-cracking　measures　should　be　employed　to　avoid　the　joint　action　of　material　uneven　stress　and　initial　crack.