The invention relates to a grain puffed particle containing quinoa and a preparation method thereof. The grain puffed particle is prepared from the following raw materials in parts by weight: 5-9 parts of quinoa flour, 1.5-2.5 parts of whole oat flour, 1-3 parts of highland barley flour, 2-5 parts of naked barley flour, 0.1-1 part of white granulated sugar, 0.1-1 part of soyabean protein powder, 0.1-0.5 part of soluble dietary fiber, 0.5-1.2 parts of vegetable oil, 0.01-0.20 part of phospholipid, 0.1-0.3 part of table salt and 0.05-0.15 part of edible calcium carbonate. The preparation method of the grain puffed particle containing quinoa comprises the steps of preparing flour, carrying out twin-screw extrusion, baking and screening. The prepared grain puffed particle is more complete in nutrition; the requirements of consumers on nutrition and health can be met.