The invention discloses an enteromorpha 
polysaccharide having 
immunocompetence and a preparation method thereof. The enteromorpha 
polysaccharide having 
immunocompetence is a 
polysaccharide HT-II. The enteromorpha polysaccharide having 
immunocompetence is a white floccule, can be well dissolved in water and 
dimethyl sulfoxide, has relative molecular weight of 96kDa, and mainly comprises glucose and 
mannose, wherein a ratio of rhamnoside to 
xylose to mannoside to glucose is 36: 20: 6: 38. The preparation method comprises the following steps of breaking down, carrying out extraction at a temperature of 90 DEG C by water, filtrating, merging the extract, concentrating, carrying out 
precipitation by 
ethanol, removing proteins, carrying out separation and purification, and carrying out 
freeze drying to obtain the purified enteromorpha polysaccharide having immunocompetence. The preparation method is simple, has stable performances, a low cost and a large medical value, can reduce 
cholesterol content and can improve 
immunity. The preparation method adopts extraction, 
protein removal and purification processes, and scientific experimental means, is a novel method for controlling enteromorpha, and provides a novel approach for controlling enteromorpha. The preparation method of the enteromorpha polysaccharide having immunocompetence develops enteromorpha medical values and purposes, controls environmental 
pollution, reduces a clean-up cost, improves 
economic benefits and is an ideal special preparation technology for enteromorpha control and integrated utilization.