The invention provides a cable support device and a fully-mechanized excavating machine operation system. The cable support device comprises a slippage rope, a guide frame, a support rod and a hanging pulley, wherein one end of the guide frame is provided with a projected part; the other end of the guide frame is provided with an extending-out part; the extending-out part is provided with a guide hole; the middle part of the guide frame is connected with a transfer loader; one end of the slippage rope is connected with one end, near a fully-mechanized excavating machine, of a belt conveyor; the other end of the slippage rope is connected with one end of the support rod; the slippage rope bypasses the outer side of the surface of the projected part and passes through the guide hole; the other end of the support rod is connected with the belt conveyor at one side, far away from the fully-mechanized excavating machine, of a lap joint position of the belt conveyor and the transfer loader; the hanging pulley is glidingly arranged on the slippage rope positioned between the guide frame and the support rod; and the hanging pulley is fixed with a trailing cable used for supplying electricity to the fully-mechanized excavating machine. The invention provides a solution that the trailing cable can automatically move along with the fully-mechanized excavating machine when the fully-mechanized excavating machine forwards and backwards moves.