Abstract: In order to improve the stability of astaxanthin, astaxanthin-loaded nanoemulsions were prepared through high-pressure homogenization, with lecithin as emulsifier. Based on single factor experiments, the nanoemulsions conditions were optimized using response surface methodology. A mathematical regression model was established for predicting the particle size of nanoemulsion and the concentration of astaxanthin at different levels of proportion of emulsifier, oil-water ratio and addition of astaxanthin. The optimal nanoemulsions conditions were determined as follows:1% (w/w) emulsifier prepared at 55℃ with 45 min, a ratio of oil-water of 1:8.5, 0.5% (w/w) astaxanthin. Under the optimized conditions, the nanoemulsion's particle size was 238.84 nm and the concentration of astaxanthin reached 90.41%.