Multimode damping of a stay cable attached with a negative stiffness device（NSD）and a linear hys? teretic damper was studied. The frequency equation of a cable under transverse control forces at two locations is used for damping analyses by considering arbitrary NSD and damper locations. The effects of NSD and damper locations， damper parameters and negative stiffness values on multimode damping of stay cable are examined. It can be found that the multimode cable damping values can be significantly enhanced comparing with the single linear hysteretic damper. The closer the installation locations，the higher the damping level. Furthermore，multimode damping effect of the combinations is verified by using a long stay cable installed with a viscous shear damper on the Sutong Bridge， together with an inertial damper. The feasibility of the NSD is carefully discussed. The results show that the NSD is more helpful to enhance the multimode damping comparing with the inertial damper.