Abstract: The use and further developing of air-textured yarn in daily textiles, especially in costume was restricted mainly by its high valued bending stiffness. The results from cantilever measuring proved that the air-textured yarn was 2 times harder than classic yarn of similar linear density, such as cotton or woolen yarn. The entanglement structure from the disordering of the fiber alignment served the stiff performance to the yarn, at the same time, it could be classified by entanglement degree. Optimization of the air-texturing parameters could fulfill an adjustment in relative small scope, while the multi-texturing would work more efficient by adjusting the value of entanglement degree. It had been proved that, the differential shrinking could cut down the bending stiffness of the air-textured yarn remarkable in case of the differential shrinkage was bigger than 10%.