The invention provides a triangular yokeplate clamping apparatus, a double-string strain insulator replacing device and a double-string strain insulator replacing method. The clamping apparatus is provided with two parallel separated and opposite clamp plates, wherein a lock pin capable of jacking or releasing the vertical edge of a triangular yokeplate is arranged between the front ends of the two clamp plates; a support surface capable of being abutted against the inclined edge of the triangular yokeplate is arranged between the back ends of the two clamp plates; during the installation, the triangular yokeplate is clamped between the two clamp plates, so that the lock pin jacks the vertical edge of the triangular yokeplate; the support surface is abutted against the inclined edge of the triangular yokeplate; and the two clamp plates are limited by a connecting element projected from the side surface of the triangular yokeplate, and cannot be upwards disengaged from the triangular yokeplate. The triangular yokeplate clamping apparatus has the advantages that the applicability is high; the structure is simple; and the operation is convenient, and the like.