The invention discloses a food grade fatty acid glycerol mixing ester preparation method which includes the steps: (1) feeding glycerol and at least two fatty acids with different carbon chain lengths into a reactor, adding catalysts, slowly leading nitrogen into the reactor and sufficiently stirring the materials; (2) performing heating reaction at the temperature controlled to range from 130 DEG C to 135 DEG C for 10-14 hours; (3) leading in the nitrogen for protection, taking away water generated in reaction through the nitrogen, condensing and collecting the water and stopping reaction until the water with theoretical weight is drained; (4) neutralizing the catalysts by neutralization liquid after reaction, controlling pH (potential of hydrogen) to range from 7 to 8, keeping the temperature of 60-70 DEG C, stirring the materials for 15-30 minutes, separating the water and washing oil with deionized water; (5) performing discoloration refining by activated carbon after washing to obtain a product. By the mode, the preparation method is simple and convenient to operate and high in conversion rate, various fatty acids react with the glycerol, and the obtained product contains various genes and accordingly is good in emulsifying effect and suitable for food processing.