The present invention discloses a preparation method of a digestion-promoting feed for taisho sanke. The preparation method comprises the following steps: firstly, weighing corresponding raw materialsincluding digestion-promoting microorganism powder, crab shell powder, a shelling agent, spirulina, astacin and carrots, then crushing and mixing parts of the raw materials, then mixing the crushed and mixed raw materials with the remaining raw materials, conducting crushing and drying, and finally conducting granulating and packaging. Various digestion-promoting microorganisms are matched to help digestion and absorption of effective components in the feed for taisho sanke in intestinal tracts, improve utilization rate of the feed and greatly reduce excreta; meanwhile, the crab shell powderand the shelling agent can supplement calcium for growth of the taisho sanke and are beneficial to development and growth of the taisho sanke; and finally, the spirulina, astacin, carrots and other coloring agents are added, so that a color increasing requirement of the feed for the aquarium fish is met, and the feed plays an important role in healthy growth and bright body color formation of thetaisho sanke.