The invention relates to the field of pharmacy, in particular to controlled release medicine for treating gastric ulcer caused by excessive gastrin secretion and a preparing method thereof. The space structure of the controlled release medicine comprises a western medicine pill core, an inner coating controlled release layer, a traditional Chinese medicine ointment layer and an outer coating layer from inside to outside. The western medicine pill core is made of lansoprazole or gelatin; the inner coating controlled release layer comprises sodium alginate, potassium alginate, pregelatinized starch, low substituted hydroxypropyl cellulose, ethyecellulose and cellulose acetate; the traditional Chinese medicine ointment layer is an ointment layer attached to the outside of the inner coating controlled release layer and comprises radix bupleuri, radix paeoniae alba, fingered citron, fried massa medicata fermentata fujianensis, liquorice, adenophora stricta miq, dried tangerine or orange peel, coptis chinensis, fructus aurantii, milkvetch roots, rhizoma corydalis and cuttlefish bone meal; raw materials of the outer coating layer include acrylic resin number IV and zein. The controlled release medicine can reasonably control gastric acid at the right moment in moderation and brings good news for patients with gastric ulcer.