The invention discloses a strain insulator string equipped with five yoke plates and three suspension points and used for an extra-high voltage direct current circuit. The strain insulator string is an insulator string formed by dish-type suspension insulators connected in series; the insulator strings are arranged in a five-cylinder shape; one ends of the two columns of the insulator strings on the edges are connected with right-angle clevises separately; the right-angle clevises are connected with suspension point fittings; one ends of the column of the insulator strings in the middle are connected with the suspension point fittings; the other ends, connected with the right-angle clevises, of the insulator strings are connected with socket clevises; two of the socket clevises are connected with a two-to-one yoke plate, so that four socket clevises are connected with two two-to-one yoke plates; the other ends of the column of the insulator strings in the middle are connected with PD clevises; the two two-to-one yoke plates and the PD clevises are connected with three-to-two yoke plates; the three-to-two yoke plates are connected with two-to-six yoke plates through two clevises; the two-to-six yoke plates are connected with strain clamps; and the strain clamps are connected with wires. The structural strength of the strain insulator string can be effectively improved.