Abstract: The dynamic viscosity of pure liquid and its aqueous solution of Tween 80 was  measured by rotational method.The result of test shows that the dynamic
 viscosity of pure Tween 80 drops with temperature up,and drops slowly as temperature comes at 45 ℃.Morsel inorganic electrolyte such as sodium citric acid doesn't have an apparent effect on the behaviour of viscosity and temperature of Tween 80 aqueous,and morsel polarity organic substance hold the dynamic viscosity of aqueous solution of Tween 80 to drop.The behaviour of viscosity and temperature of mixed system by Tween 80 and Tween 20 is between them.

Key words: Tween 80, viscosity, temperature, rotational method