Viscosity is basic index of cellulose ether used in dry-mixed mortar. Some problems need to be solved when testing the viscosity of cellulose ether solution, which includes unhomogeneity of solution, air voids in solution and different temperature in solution. Through preparing four frequently-used non-ionic cellulose ether solutions of MC, HEMC, HPMC and HEC, analyzes the factors that influencing the viscosity test results of cellulose ether solutions, such as dispersal, cooling, mixing, water replenishing, constant temperature and viscosity test process, and advances some issues needed for attention in the process of testing the viscosity of cellulose ether solution so as to assure the dependability of viscosity test results of cellulose ether solution, which includes size of test container, dispersal mode of cellulose ether powder, mixing velocity, time of ceasing mixture and the time of constant temperature etc. Keywords ：dry-mixed mortar；cellulose ether；viscosity；test