Torsional　tests　on　thirty-three　right-angle　steel　pipe　couplers　were　carried　out.　The　test　parameters　include　fastener　tightening　torques,　fastener　turnover　frequencies　and　turnover　loading　amplitudes,　etc.　The　results　showed　that　with　the　increase　of　a　fastener　tightening　torque,　the　torsional　stiffness　of　steel　pipe　coupled　joints　increase,　and　their　increase　amplitudes　under　one　failure　trial　are　more　evident　compared　to　the　turnover　tests.　The　fastener　tightening　torque　has　little　effect　on　the　torsional　stiffness　under　a　higher　turnover　loading　amplitude.　The　fastener　turnover　frequency　has　a　greater　effect　on　the　joint　torsional　stiffness.　When　the　couple　turnover　frequency　is　15　times,　the　torsional　stiffness　of　steel　pipe　joints　reach　the　maximum,　and　when　the　turnover　frequency　is　more　than　35　times,　the　torsional　stiffness　become　a　constant.　The　stiffness　of　turnover　couplers　is　greater　than　the　stiffness　under　one　failure　trial　in　the　tests.　Under　the　greater　turnover　loading　amplitude,　the　turnover　frequency　becomes　less,　and　the　torsional　stiffness　decrease　more　rapidly.　Based　on　the　test　results,　the　regression　constitutive　equation　for　torsion-rotation　relationship　is　obtained.　For　the　complicated　influences　on　the　torsional　stiffness　of　couplers　and　the　problems　hard　to　confirm　the　turnover　frequency　and　loading　amplitude,　several　effective　suggestions　on　the　construction　of　steel　pipe　supports　with　couplers　are　provided.