Abstract:The extraction conditions of polysaccharide from the residue of Haematococcus pluvialis were optimized by single factor tests and response surface methodology to improve the yield of polysaccharides.Experiments were carried out to evaluate the blood lipid-lowering effect of the obtained polysaccharide.The extraction conditions were optimized as follows：NaOH mass fraction of 2.5%,solid-to-liquid ratio of 1∶25 （g/mL）,ultrasonic power of 250 W,ultrasonic time of 10 min,and extraction time of 2.5 h.Under these conditions,the yield of polysaccharide was （5.744±0.030）%.The obtained polysaccharide at 5 mg/mL inhibited the activity of pancreatic lipase,with the inhibition rate reaching （94.19±0.02）%.