A power supply apparatus includes a power converting circuit and a modular power connection interface. By the power converting circuit, an input voltage is converted into several output voltages required for powering corresponding electronic devices. The modular power connection interface includes an output member and a connecting member. The output member includes a plurality of pins and a daughter board. The pins are arranged on at least one surface of the daughter board and electrically connected to the power converting circuit so as to transmit the output voltages. The connecting member has a first connecting part and multiple second connecting parts. The first connecting part is electrically connected with the pins of the output member, and the second connecting parts are electrically connected with corresponding electronic devices, so that the output voltages are transmitted from the power converting circuit to the electronic devices through the modular power connection interface.