The invention mainly relates to a soft capsule helpful for increasing bone density and a preparation method thereof. The soft capsule helpful for increasing the bone density is characterized by consisting of the following raw materials in parts by weight: 400-550 parts of linseed oil, 10-30 parts of red deer bone superfine powder, 10-30 parts of an astragalus extract, 10-30 parts of bone collagen, 10-30 parts of an angelica extract, 1-3 parts of vitamin D and 10-30 parts of a drynaria rhizome extract. The soft capsule disclosed by the invention, guided by theories of traditional Chinese medicine and based on modern research achievements of the traditional Chinese medicine, is careful in material selection, strict in composition and rational in combination, and is added with natural components capable of improving osteoporosis, so that the composition can tonify Qi and benefit blood, enhance immunity, relieve fatigue, strengthen tendons and bones, remove pathological wind and promote diuresis, regenerate tissue to heal wound, and integrally improve physical function, and circulations of Qi and blood are smooth, and metabolism is normal. Red deer bone functions as strengthening tendons and bones, and regenerating tissue to heal wound; drynaria rhizome can relieve joint pain, and relieve osteoporosis; vitamin D has a function of resisting rachitis, and can promote calcium absorption; astragalus can promote regeneration of injured nerve; angelica functions as replenishing blood and promoting blood circulation, regulating menstruation and relieving pain, and relaxing bowl; and linseed oil has functions of preventing and treating cancers, coronary heart disease, diabetes, prostatic cancer and other diseases. The composition is remarkable in functions of replenishing blood and benefiting blood, and strengthening tendons and bones.