The invention discloses a preparation method of beef flavor, comprising the following steps: A, tallow is put into a reaction container, heated at the temperature of 120 DEG C to 160 DEG C and stirred slowly. When the temperature of the tallow is up to 120 DEG C to 160 DEG C, the air pump works with the air pump adjusting flow of 0.4 to 0.8L/min*100g. After reacting for 2 to 4 hours, the heating is stopped and the temperature is decreased to 45 DEG C to 55 DEG C, the oxidized tallow is prepared. B, the Maillard reaction is adopted, the pro rata raw material is putted into the container, and the pH is adjusted to 6.5 to 7.5, the container is putted into the pressure reactor and heated to 110 DEG C to 130 DEG C; after reacting for 3 hours, the container is taken out and cooled to 48 DEG C to 60 DEG C, antiseptic and thickening agent are added into, to be stirred uniformly to obtain beef flavor paste, or powder is added and stirred uniformly to get beef flavor powder. The beef flavor of the invention has advantages of lifelike characteristic aroma, no need of extraction, less delamination of liquid flavor, large reduction in the manufacture cost.