Abstract: Haematococcus pluvialis powder was used as raw material,ethyl acetate and ethanol(volume ratio 1∶1)was selected as the best extraction solvent. Taking astaxanthin yield as the evaluation index and ultrasound power,extraction time,and extraction temperature as the factors,and fixing radio of solution to material 100∶1,the ultrasound method for extracting astaxanthin was researched. And then,based on the single factor experiment,the optimum conditions to ultrasound extracting astaxanthin from Haematococcus pluvialis were got by response surface methodology. The results showed that the effect of the extraction conditions was time >temperature > ultrasound power, and the optimum extraction conditions were ultrasound power 200 W, time30 min,temperature 25℃. Under this condition,the extraction rate could reach 1.045% and the content of astaxanthin in Haematococcus pluvialis was 1.05%. The optimized model by RSM agreed well with practice.