The aim of this experiment is to optimize the spray drying yield of egg liquid. The yield of whole egg powder and the function indexes of protein content, fat content, phospholipid content and water content of egg powder were obtained by orthogonal test under different processing parameters. The Mathematical model was established by Matlab software, which associated the processing parameters with the egg powder yield, protein content and water content. The mathematical models were optimized with the core index of protein yield. The optimum processing conditions for spray drying were: the inlet air temperature 180 ℃, the egg liquid concentration 0.25 g/mL, the feed rate 7.4 g/min, and the airflow rate 10 L/min. Under the optimized conditions, the yield of whole egg powder reached 78.64%. The contents of protein, water, fat and phospholipid in the whole egg powder were 40.28%, 1.71%, 54.53% and 7.16%, respectively.