The invention discloses a concentrated feed for lactating sows, and belongs to the field of pig feeds. A premix comprises lactose, glucose, calcium powder, methionine, choline chloride, threonine, an acidifying agent, a flavoring agent, vitamins for porkets, microelements for the porkets, sodium bicarbonate, eggs, chestnut kernel meal, peanut kernel meal, 98.5% lysine, sweet potato stems, sweet potato leaf meal, dried potato meal, pig sprouts, plantain herb, millet, sorghum, ethoxy quinoline, green vegetables, corn flour, pumpkin, soybean curb residue and soya-bean milk. The invention also provides a preparation method of the concentrated feed for the lactating sows. The method comprises the following steps: (1) preparing the premix; and (2) preparing the feed. The concentrated feed is used for feeding the sows during late pregnancy, and is capable of promoting rapid porcine fetal growth, increasing the birth weight of piglets, ensuring the relatively large-capacity ingestion, relatively large-capacity milk production and relatively little fat loss, promoting the weaning, empathema and hybridization as quickly as possible, and effectively improving the farming income.