Aiming at the problem of stay-cable galloping caused by lighting lamps, the galloping vibration char? acteristics and the effect of increasing structural damping on galloping-vibration were studied based on the engineer? ing background of a stay-cable installed with an elliptical lamp and a rectangular box. First, the aerodynamic coeffi? cients of stay cable were measured by the force measurement wind tunnel tests. The wind attack angle range of cable vibration was predicted by using galloping force coefficient. Then, 2- dimensional and 3-dimensional vibration tests were carried out to measure the critical wind speed of galloping. The influence of damping ratio on vibration was also studied. The test results show that the maximum drag coefficient and lift coefficient of stay cables with elliptical lamp and rectangular box are 1.8 and 1.5, respectively. The static wind load on the stay cable can be increased by 83%. The influence of local bulge point light on the aerodynamic force of stay cable is small. For two-dimensional stay cables, the most dangerous wind attack angle is 8°. The minimum galloping force coefficient is -7.9 and the minimum critical wind velocity is 21.8 m/s. For three-dimensional stay cables, the yaw angle of vibration is 40°~56° and 186°~ 196°. Both in-plane and out-of-plane vibrations occur. When ζ is 0.1%, the critical velocity is 4.7 m/s. The vibra? tion amplitude increases linearly with the increase of wind velocity. When the reduced wind velocity is 77, the dimen? sionless displacement can reach 2D（D is the diameter of stay cable）. Increasing the damping can reduce the ampli? tude of vibration at the same wind velocity. When the damping ratio is less than 0.8%, the effect of increasing damp? ing on the critical wind velocity is limited. If the damping ratio is increased to 1.0%, the galloping vibration of stay cables installed with elliptical lamps and rectangular wire boxes can be effectively suppressed.