The invention proposes a multistage wavelength-division-multiplexing ring light network, and the network comprises a data transmission plane and control nodes unified in the whole network. The data transmission plane comprises p parallel first-stage rings, m second-stage rings, and a frame top/cluster switcher connected with the second-stage rings, wherein the first-stage and second stage rings are connected with each other through transannular frame top/cluster switchers. The network employs the technology of wavelength division multiplexing, is high in speed, is large in capacity, is good in extendibility, employs the wavelength information to carry out the internal frame-crossing data exchange of a data center, and partly irons out the defects of a conventional tree-shaped network in the data center. A wavelength division multiplexing looped network in the above structure just can be applied to a switching network where C band can achieve 256000 servers through calculation, thereby providing technical reference for the design of the switching network of a large-scale data center. Meanwhile, the network can be used for the exchange among high-performance computer CPU clusters, and also can be used for an end-end switching optical network for telecommunication business.