This paper designs a new type of metering seal and automatic ensealing machine according to the structural feature of the seal. The metering seal uses buckle type structure, which is simple and reliable, to achieve high efficiency of ensealing. This metering seal can be widely used in the measuring instruments of electric power, such as intelligent electric energy meter and acquisition terminal, etc. The automatic ensealing machine uses modular design, and works in two modes: online and offline. This machine has functions of automatic ensealing, successful validation, laser marking 2D bar code and its quality testing. All these are working on the automatic verification line. It improves the verification efficiency of the measuring instruments of electric power.