Carboxymethyl Chitosan, the higher derivation of chitosan, is made in the reaction of chitin and chloride acetic acid in alkalinity circumstance. Compared with chitin, it is of higher improved physical and chemical capability, entirely 100% saluted in water and can strongly absorb the heavy metal. This kind of neutral, natural, univalent product has much more advantages in the field of health-protecting, industry and agriculture,etc. And now the product has been applied in the advanced cosmetic industry, and also has been used to reduce heavy metal, sustained release dosage of the medicine, accelerate plant growth, and clean dirty water, etc. As the medicine protecting health, this product not only keep the advantages of chitosan for protecting health, also have some much more advantages of sweet taste for the health. After eaten, it can be converted and analyzed into hypomolecule which can be easily absorbed.