This　paper　investigated　the　seismic　behavior　of　a　prefabricated　steel　braced　frame　structure　with　hinged　joints.　Six　steel　frame　specimens　with　different　enclosure　walls　were　tested　under　pseudo-static　loading.　The　results　indicated　that　the　vertical　load　of　the　hinged　braced　frame　system　was　mainly　resisted　by　the　beam　and　column　members,　and　the　lateral　stiffness　was　completely　provided　by　the　bracing　members.　The　final　failure　mode　of　all　specimens　was　the　failure　of　the　bracings,　while　the　beam-column　members　and　the　joints　remained　largely　intact.　The　rigidly　braced　specimen　was　mainly　damaged　by　buckling,　yielding,　and　tearing,　and　the　flexibly　braced　specimen　was　mostly　damaged　by　buckling,　yielding,　and　node　failure.　The　energy　dissipation　of　the　specimens　primarily　depended　on　lateral　force-resistant　components　such　as　braces　and　enclosure　walls.　Different　building　envelopes　exert　significant　effects　on　the　lateral　stiffness　and　energy　dissipation　capacity　of　the　structure.　The　ductility　coefficient　of　all　specimens　ranged　between　1.4　and　1.9,　which　indicates　that　the　structural　system　mainly　relies　on　lateral　stiffness　and　elastic　deformation　to　resist　earthquakes,　rather　than　structural　ductility.　The　proposed　prefabricated　steel　frame　system　with　hinged　connections　has　wide　prospects　of　application　in　economically　underdeveloped　areas　because　of　its　convenience　in　transportation　and　installation.