The present invention discloses a PCI Express interface compatible with USB interface comprising a power supply terminal and a ground terminal, in which four data terminals include two data transmitting terminals and two data receiving terminals, characterized in that the power supply terminal and the ground terminal of said interface coincide with the corresponding terminals of USB interface specification, two of said four data terminals are guaranteed to have their positions and widths overlaid with the position of terminal D+ in USB interface specification and not with the position of terminal D− in USB interface specification, and the other two data terminals are guaranteed to have their positions and widths overlaid with the position of terminal D− in USB interface specification and not with the position of terminal D+ in USB interface specification. The PCI Express interface compatible with USB interface can provide a data transmission rate up to 3 Gb/S according to PCI Express interface specification and support to the conventional USB peripheral devices without any modification on them. It further has the advantages of small-sized outline and convenience in use.