A multiple-in-one retaining seat comprises a retaining seat; two lateral front sides of the retaining seat being installed with two frames; a lower side of the center of the retaining seat being installed with a receptacle for receiving the personal digital assistant; an interface cartridge inserted in the retaining seat for transferring received signal to the personal digital assistant through the retaining seat; a circuit board installed in an embedding groove at an upper end of the backside of the retaining seat; the circuit board being connected to a slot seat; a lateral side of the embedding groove being protruded with a mask for receiving a speaker; the speaker being electrically connected to the circuit board for providing a hand free function; a slot being formed in the slot seat for receiving the interface cartridge; and two guide posts are installed on the retaining seat for positioning the interface cartridge.