A multifunctional complex power supply device has an anti-countercurrent and voltage-regulation circuit with a rechargeable battery connected in conjunction with a solar battery, a generator and a microphone. A first switch is mounted between the solar battery and the anti-countercurrent and voltage-regulation circuit, a second switch is between the generator and the anti-countercurrent and voltage-regulation circuit, and a third switch is between the microphone and the anti-countercurrent and voltage-regulation circuit. When using the power supply device, one of the switches is selected and the solar battery, generator or sound sounds input into the microphone can charge the rechargeable battery.