Abstract: Mode division multiplexing, as one of independent multiplexing dimensions of an optical signal, has drawn a lot of research interest in recently years. This paper reviews the related works concerning on-chip mode division multiplexing technology based on a silicon chip. Some core components and structure, as well as their performances, are discussed, such as, bus waveguides, (de)multiplexers, interfaces to multimode fibers, multimode switches, etc. The working principles of them are introduced, together with some comparative analyses. Future trend for this type of on-chip mode division multiplexing is also discussed.