The invention belongs to the technical field of beef processing, and particularly relates to roasted beef and a preparation method thereof. The roasted beef is prepared from, by weight, 95-100 parts of beef, 1.2-1.5 parts of salt, 0.1-0.3 part of sodium ascorbate, 1-2 parts of trehalose, 0.4-0.6 part of yeast extract, 0.3-0.5 part of powdery soy sauce and 0.3-0.5 part of white pepper. The roastedbeef is free of color former, long in color and luster maintaining time, proper in taste and rich in flavor and nutrition.