Abstract: A series of unifactor experiments concerning several parameters of filaments and texturing had been designed as the first step heading for the final designing and controlling of textured yarn′s structure and properties.It had been proved that the bulkiness of the differential shrinkage filaments air-jet textured yarn could be controlled effectually by the different filament or multi-filament linear density,as well as the air-jet texturing and differential shrinkage parameters.The overfeed and feeding method in air-texturing,the differential shrinkage rate and average shrinkage in differential shrinking could affect the bulkiness of differential shrinkage filaments air-jet textured yarn remarkably.