The contrast mixing experiments of easy-clean, plant-scale twin-shaft paddle mixer and V-type mixer with one over ten thousand of the tracer were carried out. The results showed that the coefficient of variation of horizontal twin-shaft paddle mixer was under 3% after 180 s mixing, while that of V-type mixer was under 4% after 20～25 min mixing. However, the different characteristics of materials should be considered in the design of this equipment.