This paper gives a description on the oxidation-degradation of lignin and the preparation of holocellulose from plant material by the sodium chloride method with different reaction time and temperature. It presents the data and figures to illustrate the relationship between holocellulose and acid-insoluble lignin, and explains the total residual lignin as the sum of acid-insoluble lignin (Klason lignin) and the acid-soluble lignin in holocellulose. The results are. 1. the holocellulose content is linear with the total residual lignin; 2. under the condition of same content of total acid-insoluble lignin in the plant material, holocellulose gained at room tempereture condition has a higher yield than that at 75℃; 3. since the acid-soluble lignin content is 50% of the total residual lignin it is necessany to determine the contents both acid-soluble lignin and acid-insoluble lignin so as to correct the content value of the holocelluse.