The invention relates to a soft 
capsule for preventing and treating Alzheimer's 
disease and a preparation method of the soft 
capsule. The soft 
capsule is prepared from the following raw materials in parts by weight: 60 to 80 parts of 
acer truncatum bunge seed oil, 10 to 25 parts of 
phospholipid, 6 to 8 parts of seville orange flower, 4 to 7 parts of 
lycium ruthenicum, and pharmaceutical excipients for the soft capsule. According to the capsule, a large amount of 
acetylcholine can be generated in a body, the content of the 
acetylcholine in a brain of an Alzheimer's 
disease patient is increased, and information conduction is enhanced, so as to activate brain cells and improve memory and intelligence level. The capsule contains natural 
nervonic acid; the 
nervonic acid is a unique 
chemical substance which is recognized in the present world and can be used for repairing damaged nerve fibers, and can promote repair and regeneration of the damaged nerve fibers, thereby improving the memory and the intelligence level. Meanwhile, the soft capsule also has the effects of improving the activity of NK cells and enhancing 
cellular immunity and 
humoral immunity, thereby improving human immune functions. The seville orange flower has the 
efficacy of activating Qi and easing middle jiao, and regulating Qi and soothing the liver, thereby relieving 
depressive symptoms of the Alzheimer's 
disease patient.