The invention relates to an elastic supporting spacer used between suspension insulators. Each insulator string comprises a triangular plate, an II-shaped insulator string assembly and a horizontal connecting member, wherein the II-shaped insulator string assembly is arranged at the two ends of the triangular plate vertically and consists of the insulator strings, connecting plates and suspension plates; the horizontal connecting member is connected with the insulator strings in a horizontal direction; the horizontal connecting member is a cross-shaped member formed by two T-shaped connecting pieces connected through a damping member; connecting assemblies movably connected with the insulator strings are arranged at the two ends of the horizontal connecting member; the damping member comprises damping springs arranged in parallel; and connecting holes, connected with the two ends of the damping springs, are formed in the T-shaped connecting pieces. By adding the spacer between the suspension insulator strings in a power transmission line, the integrality of the insulator strings is improved, the problem of mutual swinging between suspension insulators is solved, and the safety and reliability of the circuit are improved.