Abstract: A USB socket connector includes a columnar housing, a circuit board, and an expansion board. The columnar housing has a front portion and an opposite rear portion. The columnar housing includes an accommodating slot recessed from the front portion toward the rear portion and a receiving slot recessed on the rear portion and in air communication with the accommodating slot. A cross section of the receiving slot is larger than that of the accommodating slot. The circuit board includes a tongue plate portion arranged on one side thereof and having a USB3.1 Type-C interface. The circuit board is inserted into the accommodating slot, and the tongue plate portion is arranged in the front portion. The expansion board is substantially and perpendicularly connected to an end of the circuit board away from the tongue plate portion, and the expansion board is arranged in the receiving slot.