The utility model discloses a clamping groove connecting piece, it includes the rectangle body of being made by transparent material, run through the passageway that is formed with a power supply card and passes about rectangle body middle part, rectangle body one end border is equipped with the rubber layer, and other end border is equipped with the baffle, the rectangle body is close to on the outer wall of baffle one end the longitudinal symmetry and is equipped with two fixture blocks, and the one side of keeping away from the baffle on two fixture blocks all is formed with the chamfer. The utility model discloses a design has compensatied the matching defect between ammeter case and smart electric meter draw -in groove, and the emergence number of times of card trouble will the to a great extent reduction be got to its popularization and application, improves the convenient degree that the electricity was purchased to customer's plug -in card. Simultaneously, the clamping groove connecting piece cost belongs to disposable input, can effectively avoid getting the emergence of card trouble many times, reduces the metering device's of enterprise fortune dimension cost, practices thrift the manpower and material resources resource, improves the economic benefits of enterprise.