A docking station applied to a portable electronic device includes a casing module, a circuit module, a first input/output module and a second input/output module. The casing module has a casing, an opening formed on the casing, and a cover pivoting around the casing in order to selectively open or close the opening. The circuit module is disposed inside the casing. The first input/output module is disposed on the casing and electrically connected between the circuit module and a plurality of different peripherals. The second input/output module is disposed on the casing and electrically connected between the circuit module and an external connector of the portable electronic device. Therefore, when a rear side of the portable electronic device pushes the cover, the cover is opened in order to make one part of the rear side of the portable electronic device pass through the opening and receive in the casing.