A prestressed suspension structure is a type of structures that allows covering long spans due to rational use of structural materials. Prestressing of a suspension structure allows minimizing cinematic displacements. The prestressed suspension structure with the main span equal to 200 m was considered as an object of investigation. Replacement of a single steel main cable of the prestressed suspension structure by the hybrid composite cable with CFRP (Carbon Fibre Reinforced Polymer) middle layer and external steel layers with cross-section variable by the cable length considerably decreases dead weight of the cable. Hybrid composite cable ensures functioning of the structure in case of destruction of the middle CFRP layer. The considered prestressed suspension structure was investigated by the FEM software ANSYS. Rational steel distribution by the cable length was determined by optimization. Behaviour of the hybrid composite main cable in the case of destruction of the middle CFRP layer was experimentally tested using the physical model. The dynamic coefficient was obtained.