The invention relates to a method for synchronously extracting protein from rice and needle mushroom dreg. According to the method provided by the invention, the rice and the needle mushroom dreg areused as raw materials, and the raw materials are subjected to grinding, sieving, homogenization, freeze thawing and ultrasonic wave assisted alkali extraction to prepare compound powder protein, wherein the purity of the protein is 62 percent to 83 percent. Compared with a technology of extracting raw material protein separately and then compounding, the method for synchronously extracting the protein from the rice and the needle mushroom dreg, disclosed by the invention, is simpler, and the energy consumption is reduced by 15 percent to 30 percent; an obtained compound protein powder producthas the advantages of low allergy, high nutrient value, easiness for digestion and the like.