A wearable electric device includes a main body with a circuit module inside and at least a detachable battery strap with a battery module inside, and the main body and the detachable battery strap are detachably fastened together. A female buckle member is formed on the edge of the main body and includes a receiving chamber, a pair of locking notches arranged on the respective sides of the receiving chamber and a plurality of metal conductive points connected with the circuit module. A male buckle member is attached on the front part of the detachable battery strap to be fastened with the female buckle member and includes a plurality of pogo pin connectors for connecting with the metal conducting points, and a locking block for fastening with the receiving chamber.