With Artemisia seed polysaccharide powder as raw material, 3-chloro-2-hydroxypropyl-trimethyl ammonium chloride (HAT) as cationic ether and isopropanol as dispersant, cationic Artemisia seed polysaccharide is prepared with catalysis of alkali. Influences of alkalization temperature and time, etherification temperature and time, ratio of alkali to HAT as well as alcohol to distilled water to the final characteristics of cold water solubility and light transmittance of the final product are studied. When the ratio of isopropanol to distilled water is 3.5∶1 and the ratio of NaOH (mol) to cationic ether (mol) is 1.5∶1, the raw material powder is etherified immediately after adding alkali at 60 ℃ for 3.5 h. The result shows that cold water solubility of the product is better than that of the raw material, and light transmission of the product reaches 80%. The structure and thermo stability of the product are characterized by FTIR and DSC.