Abstract. High strength hybrid composite cables with large specific strength on the base of such materials as carbon fiber reinforced plastics (CFRP), glass fiber reinforced plastics (GFRP) and Vectran, are widely used in constructional practice. But using of a steel component enables to increase small relative elongation, decrease brittleness and expand area of application of high strength hybrid composite cables. Steel was investigated in combination with such materials as CFRP, GFRP and Vectran. The behaviours of hybrid composite cable were investigated analytically and by experiment. Hybrid composite cables with the increased specific strength were considered as materials of several cable groups for a prestressed saddle-shaped cable roof with dimensions 50x50m. Opportunity to decrease the displacements of composite saddle-shaped cable roof by using of cable trusses, which were made from the hybrid composite cable with the increased specific strength was investigated. Rational geometric characteristics of the cable truss were determined by the numerical experiment. It was shown, that using of hybrid composite cable enables to increase its specific strength up to 2.4 times. Rational components for composite cable with increased specific strength were chosen by the numerical experiment.