Abstract: The previous studies have shown that longitudinal ribs have a good suppression effect on the wind-rain vibration of stay cables, but the influence on the wind load characteristics of stay cables is not yet clear. Two rectangular ribs with a width and height of 5 mm were arranged on the surface of the stay cable. The influence of the average wind pressure distribution in the circumferential and spanwise directions at different Reynolds numbers was studied by wind tunnel pressure measurement experiments. The results show that the ribs make the spanwise wind load of the stay cable produce a strong three-dimensionality at the separation point, and the wind load has no obvious change rule along the spanwise direction. In the double separation bubble zone, the ribs have little effect on the circumferential wind load distribution of the stay cable. The rib changes the position of the separation point, accelerates the transition from laminar flow to turbulent flow, and advances the critical region. In the region of low Reynolds number, the ribs will strengthen the three-dimensionality of the flow field on the surface of the stay cable. As the Reynolds number increases, the three-dimensionality of the flow field on the surface of the stay cable first increases and then decreases. After reaching the double separation bubble region, the three-dimensionality of the flow field on the stay cable tends to be stable.