A power connector structure is provided. The power connector includes a cable, an inner ring structure, an inner case, a strain relief structure, and an external cover. The inner case has a main body and an out-extending protrusion. The out-extending protrusion is set on the first opening proximate to the inner ring structure and elongates from an edge of the opening. The strain relief structure is set on the first opening proximate to the inner ring structure, substantially fills a gap within the opening, and covers the out-extending protrusion and a portion of the cable. The out-extending protrusion is utilized to enhance the bonding force between the inner case and the strain relief structure to improve the product reliability.