To　study　the　bending　stiffness　of　steel　tubular　truss　and　the　effects　of　chord-filled　concrete,　tests　on　three　trusses　with　rectangular　steel　tubes　and　circular　steel　tubes　were　carried　out,　the　first　was　a　hollow　steel　tubular　truss,　the　second　was　a　hollow　steel　tubular　truss　with　concrete　filled　in　the　compression　chord,　and　the　third　was　a　hollow　steel　tubular　truss　with　concrete　filled　in　both　the　compression　and　tension　chords.　The　test　results　shows:　the　joints　deformation　contribute　substantially　to　the　overall　deflection,　which　need　to　be　considered　in　calculating　the　overall　bending　stiffness　of　the　overall　truss;　the　chord-filled　concrete　improves　the　rigidity　of　overall　truss　and　reduces　the　deformation　of　the　joints.　The　filled　concrete　in　compression　chord　increases　both　the　compressive　stiffness　of　the　chord　and　the　truss.　A　simplified　method　to　calculate　deformation　was　recommended　for　the　three　trusses,　where　the　ideal　node　connection　model　is　adopted.　The　joint　deformation　is　considered　in　the　simplified　method,　and　the　lattice　deflection　amplification　factor　is　taken　to　1.15,　1.15　and　1.20　respectively　for　the　three　trusses.　Finally,　according　to　test　results,　reasonable　values　of　the　compressive　stiffness　and　bending　stiffness　of　compression　chords　were　discussed.