The invention relates to a shared optical packet exchange node structure based on internal wavelength comprising wavelength-division demultiplexer, adjustable wavelength shifter, optic switch matrix, wavelength-division multiplex, optical fiber delay line, splitter, SOA light gate, passive coupler. Using a group of shared optical fibre delay line for solving competition of light grouping, and increasing optical buffer capacity by internal wavelength method, Solving FDL competition of shared optical cache; Each optical fibre delay line being degeneratively arranged, Each optical fibre delay line cache wavelength comprising transmission wavelength in input / output optical fiber, and also increasing proper internal wavelength to enlarge capacity of optical cache according to need, introducing extra internal wavelength to optical fibre delay line to enhance capacity of FDL optical cache; Node structure with compact appearance being simply controlled. Packet loss rate can be largely reduced for exchange node without increasing optical packet cache time delay, which effectively solves FDL competition problem of shared optical cache.