Abstract: This paper is concerned with the out-of-plane inelastic stability of space truss arches with triangular sections. First, the out-of-plane elastic buckling load is derived. After that, the nonlinear inelsatic behaviors of space truss arches under uniform compression and uniform bending, respectively, are investigated, and the design equations are obtained using the normalized slenderness. Effects of component deformation on the out-of-plane strength of space truss arches are subsequently studied and accounted for in the design equations with two additional parameters. Space truss arches subjected to full-span uniformly distributed loads or half-span uniformly distributed loads are studied. Based on FEM numerical results , interaction equations for the out-of-plane strength of space truss arches considering the combination of compression and bending are proposed. These interaction equations can be used for the out-of-plane strength design of space trusses with triangular sections.