The invention discloses a pregnant sow feed for comprehensively preventing constipation of a sow. The pregnant sow feed is prepared from the components: maize, bran, ginkgo biloba leaf slags, garlic residues, sugar beet pulp, soybean hull, DDGS (Distillers Dried Grains With Soluble), bean pulp, soybean oil, mountain flour, calcium hydrophosphate, salt, potassium chloride, gypsum powder, mirabilite, rheum officinale, sodium bicarbonate, choline chloride, 30 percent glycine betaine, microecologics, xylooligosaccharide and 1 percent premix. With the adoption of the pregnant sow feed with the formula, the heat stress of the sow is weakened, the constipation occurrence rate of the pregnant sow is lowered by 20-40 percent, the previous embryo survival rate of the pregnant sow can be increased so as to enable the number born alive of the sow to be increased by 10-18 percent, the sow birth process is shortened, the piglet birth weight is increased by 10-20 percent, and the economic benefit of pig production is increased.