Plasmonic waveguides that allow deeply subwavelength confinement of light provide an effective platform for the design of ultracompact photonic devices.As an important plasmonic waveguide,metal-insulator-metal(MIM)structure supports the propagation of light in the nanoscale regime at the visible and near-infrared ranges.Here,we focus on our work in MIM plasmonic waveguide devices for manipulating light,and review some of the recent development of this topic.We introduce MIM plasmonic wavelength filtering and demultiplexing devices,and present the electromagnetic induced transparency(EIT)-like and Fano resonance effects in MIM waveguide systems.The slow-light and rainbow trapping effects are demonstrated theoretically.These results pave a way toward dynamic control of the special and useful optical responses,which actualize some new plasmonic waveguide-integrated devices such as nanoscale filters,demultiplexers,sensors,slow light waveguides,and buffers.