The present invention discloses an electric larceny prevention metering device and an electric larceny prevention method thereof. The electric larceny prevention metering device comprises a box which is capable of closing secondary wiring of current transformers, so that electric larceny cannot occur at the position of the secondary wiring. At the same time, each current transformer sleeves an electric conductor, one end of the electric conductor is fixed to a kettle head rod of a transformer, and the electric conductor is not easy to break, so that electric larceny cannot occur at the position of primary wiring, and a pressure wire at the voltage side of the transformer can be omitted. The electric larceny prevention method of the electric larceny prevention metering device can protect the secondary wiring, the primary wiring and the current transformers, in addition, connection points of the above positions are also protected, in this way, through adoption of the electric larceny prevention metering device, the positions where electric larceny is easy to occur can be closed, thereby effectively preventing occurrence of an electric larceny condition.