Objective: To optimize extraction technology and alcohol precipitation process of water-soluble polysaccharides form Meretrix meretrix

and provide experimental evidence for health products development of this effective part. Method: Content of water-soluble polysaccharides was determined by anthrone-sulfuric acid method at 625 nm.Water-soluble polysaccharides was islolated by water extracting alcohol precipitating method

taking yield

transfer rate and content of polysaccharides as indexes

process conditions were optimized by orthogonal test and single factor test. Result: Optimum process conditions for water-soluble polysaccharides were as followings:extracted thrice with 3 times the amount of water at 80 ℃

40 min for each time

extract concentrated to half of raw material

added ethanol to volume fraction of 80%

alcohol precipitation for 12 hours

dried at 60 ℃.Under these conditions

average yield of water-soluble polysaccharides was 7.71% and its average content was 42.53%. Conclusion: This optimized technology is stable and feasible with high extracting rate and transfer rate of water-soluble polysaccharides in M.meretrix

it can balance purity and extracting rate of this effective part.