Spatial steel truss with the span equal to 60 m was investigated. The truss is with the parallel chords and triangular lattice. The minimum recommended height of the truss equal to 3m was adopted. The elements of the truss is the round welded pipes. The dependences of material consumption on the angles between the elements of lattice and angle between grains of the spatial truss were obtained for three grades of steel. The dependences of the maximum vertical displacements of spatial truss on the angle between the elements of lattice and the angle between grains of the spatial truss also were obtained. The dependences were obtained for the case, when the structure is loaded by the design vertical load, which includes snow and structural dead weight. Two limit states were taken in to account. It was shown, that the rational from the point of view of materials consumption angle between the elements of lattice and the angle between grains of the spatial truss are equal to 45 and 30 degrees, correspondingly. The usage of high-strength steel is not rational for such kind of trusses. Vertical displacements of spatial truss are greater for high-strength steel trusses with greater angle between the elements of lattice and greater angle between grains.