The invention discloses premixed flour for buckwheat steamed buns and a production process thereof and belongs to the technical field of foods. The premixed flour for buckwheat steamed buns comprises,by weight, 60-80 parts of wheat flour, 5-25 parts of buckwheat flour, 5-25 parts of puffed buckwheat flour, 0.7-1.2 parts of microcapsule-embedded high-activity dry yeast, 0.05-0.2 part of sodium stearoyl lactylate, 0.05-0.2 part of calcium stearoyl lactylate, 0.01-0.02 part of vitamin C and 0.005-0.02 part of an enzyme preparation, wherein the mass ratio of the buckwheat flour to the puffed buckwheat flour is 1: 5 to 5: 1; the microcapsule embedded high-activity dry yeast is an industrial instant dry yeast of lesaffre; the moisture content of the premixed flour for buckwheat steamed buns is10% or below. By adopting the buckwheat steamed bun premixed flour, the quality of the buckwheat steamed bun is improved, the increase of a fatty acid value can be effectively delayed, the rancidity is prevented, the inactivation of the yeast and enzyme preparation is delayed, the quality guarantee period of the premixed flour for buckwheat steamed buns is prolonged, and the industrial productionof the premixed flour for the buckwheat steamed buns is achieved.