Abstract: Besides material, weave, spinning form and color, the design of slubby yarn also contributes a lot to the style of denim fabric. The parameters influencing the style of denim fabric include slub length, slub distance, slub multiple and slub density, which are also the key elements for designers to grasp fashion trend of denim fabric. Starting with discussing the influential factors in designing slub yarn, the article analyzed and determined these parameters.

Key words: denim fabric; slubby yarn; flat yarn; yarn number