In　the　braced　excavation　engineering,　steel　tube　bracing　consists　of　steel　tubes　and　active　node.　Most　of　the　studies　on　the　active　node　remain　qualitative　and　there　is　no　reliable　quantitative　calculation　or　experimental　data.　In　order　to　quantitatively　study　the　mechanical　characteristics　of　active　node　and　the　effect　of　the　active　node　on　the　support　system,　the　indoor　test　of　the　active　nodes　and　the　theoretical　calculation　of　the　steel　supports　were　carried　out,　and　comparative　analysis　showed　that:　The　yield　load　and　stiffness　of　three　active　nodes　are　highly　discrete.　The　active　node　determines　the　overall　bearing　capacity　of　the　support　system.　Copyright　©　Soil　Mechanics　and　Geotechnical　Engineering,　ARC　2019.All　rights　reserved.