Chlorophylls were extracted by using ultrasonic from Spirulina platensis.Single factor examination and response surface analysis experiments were adopted to investigate the effects of extraction time,extraction solvent,solvent concentration,ratio of liquid to solid and extraction grade.The results showed that the optimal process parameters for this method were:extraction time of 56.5 min,ethanol concentration of 48.3%(vol) of ethanol/acetone solvent,and ratio of liquid to solid of 7.9 ml·g-1.The optimized chlorophylls extraction yield was 1.28%.The comparison experimental results indicated that the yield of chlorophylls by ultrasonic extraction was higher than that obtained from conventional solvent extraction.