The invention relates to a copper wire shielded medium-voltage optical fiber composite cable and a shielding device for a smart grid. The composite cable includes a conductor, a conductor shielding layer, an insulating layer, an insulating shielding layer, a semiconductive buffer layer, copper wire, and a metal temperature measuring optical unit. , copper belt, outer sheath, metal temperature measuring optical unit including optical fiber, fiber paste, stainless steel tube; Pay-off stand, cage-type automatic back-twist pay-off stand, metal temperature measuring optical unit can be fully back-twisted, automatic pay-off, and finally achieve the purpose of accurate temperature measurement of each transmission conductor, achieve real-time monitoring of cable operation, and real-time control of power grid operation status, quickly diagnose and eliminate potential faults; with as little manual intervention as possible, quickly isolate faults, self-recovery, avoid large-scale power outages, and ensure the power supply security of the main line.