The invention discloses a rapid locking cable clamp for an electric power circuit, which is characterized by comprising a cable clamp body, a cover plate, a hinge shaft, a lock tongue spring, a hinge pin and a limiting body, wherein the cable clamp and the cover plate are connected by the hinge shaft, a lock tongue is installed on the cable clamp body through a lock tongue hinge pin on which a spring is arranged, the spring enables the lock tongue to have an anticlockwise torque surrounding the hinge pin, the tail end of the cover plate is provided with a stop block, and the lock tongue is incontact with the stop block; after the cover plate and the cable clamp body are closed tightly, the lock tongue locks the cover plate tightly and is in a self-locking state, and the initial position of the lock tongue before online clamping operation can be limited by the limiting body. The rapid locking cable clamp has simple operation, safety and reliability, can be suitable for live working ofoverheadlines, automatic installation of power equipment and rapid locking of line material and hardware fittings. The invention can simplify the three-four original actions into one action for finishing installation operation, not only ensure the line installation, but also ensure that the construction is simple, convenient and feasible.