The　seismic　behavior　of　an　embedded　concrete-filled　steel　tubes　(CFST)　precast　column-to-cap　beam　socket　connection　of　a　practical　engineering　project　was　investigated　through　1:3-scale　quasi-static　tests.　The　precast　column　and　cap　beam　was　integrated　by　ultrahigh-performance　concrete　(UHPC)　grouting　to　improve　the　interface　bonding　behavior　and　lateral　constraint.　The　influences　of　embedment　depth,　socket　forming　method,　and　column　section　size　on　the　cyclic　response　of　the　structure　were　evaluated.　The　experimental　results　revealed　that　when　the　concrete-filled　steel　tube　(CFST)　embedded　depth　is　1.0　times　tube　diameter,　the　specimens　can　obtain　good　strength　and　hysteresis　performance.　The　socket　hole　formed　by　a　steel　pile　can　further　promote　the　hysteresis　performance　of　the　cap　beam-column　joint,　and　the　ultimate　failure　of　the　joint　is　the　fracture　of　the　column　longitudinal　rebar.　A　model　for　evaluating　the　moment　capacity　of　the　CFST　socket　connection　was　proposed　and　verified　by　the　test　results,　which　can　be　used　in　the　preliminary　design　the　proposed　connection.