A control device including a first shell; a battery pack mounting part; a first control unit, which is provided in the first shell and is used for cutting off power transmission from a battery pack to an electric power tool when the battery pack is abnormal; a first user operation unit, which is arranged on the first shell and is operated by a user to control the electric power tool; and a first interface, electrically connected to the first user operation unit. An electric power tool system comprises the control device and the electric power tool. The control device can be adapted to different types of electric power tools, and the control device is not provided with a control portion used for adjusting working parameter of the electric power tool, such that the control device can more flexibly match an upgraded new electric power tool.