A Universal Serial Bus (USB) port tester for testing a USB port of an electronic device includes an interface unit, a current-testing unit, and a voltage-testing unit. The interface unit is used for electrically connecting with the USB port of the electronic device and a USB device. The current-testing unit is connected to the interface unit for testing quality of the USB port of the electronic device in a standard current range. The voltage-testing unit is connected to the interface unit for testing quality of the USB port of the electronic device in a standard voltage range.