The　beam-to-column　connection　with　cantilever　beam　segment　is　one　of　the　connection　design　forms　recommended　by　the　Code　for　seismic　design　of　buildings.　In　order　to　study　the　seismic　behavior　of　beam-to-column　connections　with　cantilever　beam-segment　made　by　LY315　steel,　the　anti-slip　coefficient　tests　of　high-strength　bolt　and　the　cyclic　loading　tests　of　beam-to-column　connections　were　carried　out.　The　failure　mode,　hysteretic　curve,　skeleton　curve　and　ductility　coefficient　of　connections　were　obtained.　Furthermore,　the　influence　of　the　length　of　cantilever　beam　on　the　seismic　behavior　of　connections　was　discussed.　The　results　show　that　the　anti-slip　coefficient　of　bolt　with　surface　treatment　of　using　wire　brush　to　remove　floating　rust　is　0.29　for　LY315　steel.　Besides,　the　hysteretic　curves　of　the　specimens　are　plump,　and　the　beam-to-column　connections　present　good　energy　dissipation　capacity.　Moreover,　the　ultimate　rotation　angles　of　the　three　specimens　exceed　0.04　rad,　and　the　ductility　coefficients　of　the　three　specimens　are　more　than　4,　which　indicates　the　connections　have　good　deformation　performance　and　ductility.　With　the　increase　of　the　cantilever　beam　length,　the　cumulative　energy　dissipation　of　the　specimens　decreases,　which　may　be　caused　by　the　slip　energy　dissipation　of　the　bolt.　On　the　other　hand,　with　the　increase　of　the　cantilever　beam　length,　the　bearing　capacity　increases　slightly,　and　the　change　of　the　cantilever　beam　length　has　little　effect　on　the　ductility　and　stiffness　degradation.　©　2021,　Editorial　Office　of　Journal　of　Building　Structures.　All　right　reserved.