A battery cover mechanism includes a body member, a battery cover and an operating piece. The body member defines a receiving cavity recessed therefrom for receiving the battery cover and a battery therein. The battery cover is rotatably assembled to the body member to cover the receiving cavity of the body member. The operating piece is releasably assembled to the battery cover for locking the battery cover to the body member and unlocking the battery cover. The battery cover mechanism is convenience to operate, and avoids the interfering signals efficiently.