The invention discloses a walnut-perilla-fish oil capsule for preventing and treating memory decline and insomnia. The capsule comprises the following components: 12-15 parts of walnut oil, 5-6 partsof fish oil, 5-8 parts of wheat germ powder, 5-10 parts of perilla oil, 10-15 parts of fructus alpiniae oxyphyllae, 5-8 parts of corn starch, 8-10 parts of skimmed milk powder, 5-8 parts of rhizoma acori graminei, 5-8 parts of fructus lycii, 5-8 parts of fructus schisandrae chinensis, 5-8 parts of lilii bulbus, 5-8 parts of American ginseng ferment powder, 3-5 parts of ginkgo leaf, 2-3 parts of lysine, 1-2 parts of leucine, 3-5 parts of monoammonium glycyrrhizinate, 2-3 parts of Chinese date and 3-4 parts of xylooligosaccharide. According to the capsule, the American ginseng ferment powder with high saponin content, the monoammonium glycyrrhizinate and other components containing brain-invigorating and intelligence-benefiting components are reasonably compounded, so that the capsule is suitable for teenagers, high-strength mental workers and middle-aged and old-aged people with memory decline, and has effects of invigorating the brain and benefiting intelligence, calming the heart andtranquilizing the mind, and improving the memory.