The utility model discloses a detection device for the motion state of a live-line insulator, solving the technical problem that live-line detection for a high-voltage power transmission and transformation line insulator cannot be carried out by a conventional device. The detection device for the motion state of the live-line insulator comprises a single-chip microcomputer(1) and a miniature power gearbox (2), and a motion rod (3) is movably arranged in the miniature power gearbox (2); one end of the motion rod (3) is fixedly equipped with a detection rod (4) of which the top end is equipped with an electric field sensor (5), the electric field sensor (5) is electrically connected with the single-chip microcomputer (1) via an optical cable, and the single-chip microcomputer (1) is electrically connected with a driving motor in the miniature power gearbox (2). The detection device for the motion state of the live-line insulator of the utility model is simple in structure, convenient in assembly and safe in use.