HEC with a certain molar degree of substitution can play the best role in catalytic protection of colloid polymerization; it can play the best role in controlling the growth of polymer particles, stabilizing the latex performance, and resisting low and high temperatures and mechanical shear. Hydroxyethyl cellulose for emulsion polymerization,during the polymerization of latexes, Hydroxyethyl cellulose for emulsion polymerization protects the concentration of colloids within a critical range and controls the size of polymer particles and the degree of freedom of the participating groups.