Abstract: It is an important task to improve the strength of yarn,especially of the fine yarn,in friction spinning research.A great deal of experiments and analysis have been conducted in respect to the carding speed,drum speed and output speed of fine yarn spinning by friction spinning system.The experiments show that different carding speed should be used according to different fineness of yarns,and the speed should be higher for finer yarns.In order to acquire optimal strength of the yarn,friction ratio should be determined rationally when fiber output is constant.This paper has provided a basis for improving the strength of yarn of friction spinning in determining carding,drum and output speeds.