The invention discloses a kind of high-fiber bread capable of prolonging ageing time. The high-fiber bread is prepared by the materials including, by weight, 3-5 parts of oat powder, 3-5 parts of buckwheat powder, 3-5 parts of sorghum rice flour, 2-4 parts of red bean powder, 2-4 parts of red-skinned millet flour, 80-120 parts of high gluten wheat flour, 4-6 parts of active dry yeast, 2-4 parts of bread improver, 12.5-17.5 parts of soft white sugar, 0.8-1.5 parts of salt, 8-12 parts of eggs, 8-12 parts of butter, 6-10 parts of plant oil, 0.4-0.6 parts of soya bean lecithin, 0.002-0.004 parts of ascorbic acid, 0.001-0.003 parts of alpha-amylase, and 40-60 parts of water. The preparation method of the high-fiber bread comprises the steps of pretreatment of raw materials; dough mixing; primary fermentation; segmenting and shaping; proofing; baking; and cooling and packaging. The bread is high in dietary fiber content and long in aging time, bread kinds are enriched, and the preparation technology of the bread is simple.