With the NDJ-1 type of rotating viscometer,the NDJ-79 type of rotating viscometer and American LVDV-I+ Brookfield viscometer,the viscosity of sodium carboxy methyl cellulose(CMC)was comparatively studied.Results showed that with the viscosity of 1% or 2% CMC solution heighten,the viscosity curve of three viscometers showed that the viscosity of the NDJ-1 type of viscometer was higher than Brookfield viscometer,the viscosity of Brookfield viscometer was higher than the NDJ-79 type of viscometer.The viscosity of the NDJ-79 type of viscometer slowly increased,and the disparities were more and more big compared with the NDJ-1 and Brookfield type of viscometers.The NDJ-1 type of viscometer compared with Brookfield type of viscometer,1500 mPa·s(1% NDJ-1 type viscosity) was the 1% viscosity changes of separate of two viscometers,2000 mPa·s(2% Brookfield type viscosity) was the 2% viscosity changes of separate of two viscometers.1% Brookfield type viscosity and 2% NDJ-1 type viscosity were a linear approximation.About 3500 mPa·s(1% Brookfield type viscosity) was the change of separate of 1% Brookfield type viscosity and 2% NDJ-79 type viscosity.1% or 2% viscosity of three viscometers were not certain corresponding relation.