The kinetics of thermal degradation of poly (p-phenylen benzobisoxazole) (PBO) were studied by thermogravimetric analysis (TG) in dynamic nitrogen gas at four different heating rates: 5, 10, 15, 20 degrees C/min. The activation energy calculated by Kissinger Method was 352.19 kJ/mol, and the mean value of activation energies evaluated by Flynn-Wall-Ozawa Method was 338.32 kJ/mol. The degradation kinetic model of PBO followed the mechanism of random scission of weak bonds of PBO molecule and impact of the active groups obtained from the broken bonds, Mampel Power equation with integral form G(alpha) = alpha(3/2) and differential form f(alpha)+ = (2)/(3)alpha(-1/2). And the mathematical equation of kinetic compensation effect was ln A = 0.1365 E-a - 1.4102. (c) 2006 Wiley Periodicals, Inc.