Optimization of the process condition for producing a low viscous carboxymethyl cellulose sodium salt (CMC) was investigated with experimental design, carboxymethyl cellulose of low viscosity was studied by'concentration of NaOH solution and oxidation reagent in isopropanol. The CMC which can be employed according to the study was crude CMC without neutralization and washing. The reaction conditions were varied to find the best process conditions for optimum reaction efficiencies and product properties. The aqueous solution viscosity of the technical CMC aqueous solution having a viscosity of 140,000 mPas for a l0% aqueous solution was decreased without lowering the CMC concentration. The viscosity of final product was 400-600 mPas for a l0% aqueous solution. The low viscosity CMC used for the industrial field (specially paper industry) was prepared through using the aqueous solution of NaOH to alkalizing wood pulp, etherifying by slurry method, adding NaOH aqueous solution and oxidizing. It's advantages are high etherifying uniformity, purity and low viscosity.