The modeling of thermal decomposition process of ten natural fibers commonly used in polymer composite industry was performed by assuming a global model occurring within the entire degradation range with consideration of fiber as one pseudocomponent. Malek method with activation energy values previously obtained was applied to the modeling process. Careful calculation and evaluation indicated that, within an acceptable error limit of 5%, RO(n > 1) model can be used to describe the degradation process of most selected fibers well. The other kinetic parameters used include activation energy range of 160-170 kJ/mol; parameter n in RO(n > 1) = (1 - alpha)'' of 3-4; and In A between 35 and 42 In s(-1). Some condition limitations of the obtained model were also discussed. The model has practical significance in predicting fiber weight loss when the fiber is used in combination with engineering thermoplastics. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 114: 834-842, 2009