Abstract: The setting principle of wool is very complex，it is now generally accepted the explanation of chemical setting theory from the micro perspective of molecular, while neglecting the effect on shape-setting caused by interaction between the fiber assembly . This paper uses fractal theory, from the macro-perspective view of interaction between fiber and fiber to analysis the principle of wool setting, given out the fractal dimension analysis and the multi-fractal spectrum analysis of setting principle. On the one hand, deeply theoretical analyzing can provide theoretical guidance for production practices and setting processes of optimization; on the other hand, the fractal phenomena in production and living also provide a wide range of realistic material for the development of fractal theory. The multi-fractal spectrum theory of fractal is even first used in textiles.

Key words: setting, fractal, fractal dimension, multi-fractal spectrum