The present invention belongs to the field of health food, and in particular relates to a vitamin D3 soft capsule and a preparation method thereof. The vitamin D3 soft capsule includes an internal contained substance and a capsule shell, the internal contained substance comprises the following components in parts by weight: vitamin D3, vitamin D2, walnut oil, eucommia ulmoides seed oil, pomegranate seed oil, amino acids, calcium citrate, an antioxidant and a stabilizer; and the capsule shell comprises the following components in parts by weight: gelatine, glycerol, titanium dioxide, and purified water. The vitamin D3 soft capsules contains a variety of vitamins and vegetable oils, can be used for supplement of a sufficient amount of vitamin D and promotion the absorption of calcium and phosphorus, can provide a variety of nutrients for the human body, and has the effects of enhancing brain function, enhance human immune function, promoting the development of the brain and nervous system, eliminating free radicals in the body, preventing a variety of chronic diseases, and the like.