The invention belongs to the technical field of feed compositions, particularly relates to a feed for laying hens in the hen laying period for extending the shelf life of an egg and a preparation method, and relates to a high-selenium egg with long shelf life by using the feed. The feed is prepared from the following raw materials of 20 to 35 parts of corn, 5 to 8 parts of soybean meal, 2 to 5 parts of extruded soybean, 3 to 8 parts of extruded flaxseed, 3 to 8 parts of corn protein powder, 2 to 4 parts of sesame meal, 3 to 8 parts of rice bran, 1 to 3 parts of pepper residue, 0.5 to 1.0 partof palm kernel oil, 1 to 5 parts of barley rootlet, 0.8 to 2 parts of biological fermenting feed, 0.03 to 0.05 part of Youkebao, 0.025 part of selenium yeast, and the like. The biological fermenting feed is prepared by mixing and fermenting coagulation bacillus, lactobacillus plantarum, lactobacillus lactobacillus and saccharomyces cerevisiae. The feed has the advantages that the feed is used forthe culturing of laying hens, the content of selenium in each is higher than 22.85mug, the shelf life is 80 days at the temperature of 4 to 8 DEG C, and the shelf life at normal temperature is 50 days.