In this article, We investigate the effects of oligosaccharide accumulated in the coagulation bath on the lyocell fiber process during industrial production. The research method consist,; of three parts. First, high-performance liquid chromatography is used to analyze the monosaccharide composition of lyocell fibers and their pulp materials to determine whether the hemicelluloses in pulp material can be precipitated from the coagulation bath and then regenerated into lyocell fibers. Second, We establish a method for measuring the total sugar mixture content in the coagulation bath, which is a necessary technique during the industrial production of lyocell fibers. Third, We study the effect of oligosaccharide accumulated in the coagulation bath oil the mechanical properties and supermolecular structure of lyocell fibers through a simulation experiment. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 113: 150-156, 2009