This paper determined the optimum producing technology conditions of chitosan monomer through lots of experiments and compared for merit and shortcoming with the former results. D-glucosamine hydrochloride is one of the derivations of chitin monomer, it is an important kind of biochemicals and intermedium of medicine, and it is well-liked in international market. We had verdict-crossing experiment with three factors and six levels. On the basis of ultimate yield, monomer content, optical rotation, chromaticity, crystal and so on, we obtained optimum technology conditions. Meanwhile, we investigated the influence of orders of filtration craft and de-colorization craft on the product quality. Our experimental products are consistent with that of sigma Corp. by IR. This work establishes an excellently technological guarantee for the future industrialization.