The present invention discloses a low-fat pastry and a preparation method thereof. The low-fat pastry is prepared from the following raw materials in parts by weight: 200-300 parts of wheat fiber powder, 100-200 parts of highland barley powder, 36-75 parts of nutritional powder, 30-70 parts of white atractylodes rhizome, 30-50 parts of carrots, 3-11 parts of peanut oil, 12-18 parts of raisins, 55-65 parts of Chinese yams, 7-10 parts of condensed milk, 10-15 parts of cape jasmine fruits, 42-50 parts of eggs, 5-10 parts of milk, 5-8 parts of honey, 1-4 parts of an assistant agent, 9-13 parts ofbutter and 1,000-1,500 parts of water; the ratios of the wheat fiber powder, highland barley powder and nutritional powder is 3:2:1; and the nutritional powder is prepared from the following raw materials in parts by weight: 10-20 parts of haw powder, 5-10 parts of red jujube powder, 7-15 parts of black fungus powder, 1-5 parts of black sesame powder, 3-5 parts of Chinese wolfberry fruit powder and 10-20 parts of corn flour. By using the method, the low-fat pastry is fragrant, sweet, delicious, balanced in nutrients, low in fat and low in sugar, reduces possibility of obesity caused by excessive consumption, and is free of any additives, safe to eat and the ideal nutritious food for consumers.