A USB connector, a PCB connected to the USB connector, and a USB device are provided. The USB connector includes a metal surface, and on the metal surface, a solid metal part is set at a location corresponding to a spring of a socket, so that the spring contacts the solid metal part after the USB connector is inserted into the socket to reduce electromagnetic interference. The USB connector may include an in-line weld leg; a metal enclosure located at the same side as the in-line weld leg fully contacts a PCB when the USB connector is connected to the PCB; and contact surfaces on the USB connector that contact the PCB are metal surfaces. The PCB includes a suppression circuit configured to suppress harmonic waves in USB data transmission.