Preparation method of cellulose ether

The invention provides a preparation method of cellulose ether. The preparation method comprises the following steps: mixing wet cellulose pulp with an organic solvent to obtain a mixture, wherein the weight moisture content of the wet cellulose pulp is 10 wt.% to 60 wt.%; mixing the mixture with an alkaline substance, carrying out an alkaline reaction to obtain an alkaline product; performing an etherification reaction on the alkaline product and an etherifying agent to obtain cellulose ether. The wet cellulose pulp is washed with the organic solvent, so that the organic solvent and water are sufficiently exchanged on the surface of cellulose, and water in the wet cellulose pulp is transferred in the organic solvent, which eliminates the step of drying the wet cellulose pulp, and lowers the cost; the damage to the structure of the cellulose during the drying process is avoided, so that the obtained cellulose ether has higher viscosity and higher degree of substitution.