The thermal decomposition of 2, 4, 6, 8, 10, 12-hexanitro-2, 4, 6, 8, 10, 12-hexaazaisowurtzitane (CL-20) is examined via a self-modified dynamic vacuum stability test at temperature intervals of 130-170 A degrees C. The p versus t curves indicate the multistep thermal decomposition of CL-20 and its autocatalytic behavior. The reaction rate constant k is 3.07 x 10(-8), 9.61 x 10(-8), 27.25 x 10(-8), 133.31 x 10(-8), and 387.94 x 10(-8) s(-1) at 130, 140, 150, 160, and 170 A degrees C, respectively. The polymorphic transformation of CL-20 and certain products may affect kinetic output. The activation energy is 182.5 kJ mol(-1), which shows good agreement with previously published results. The storage life of CL-20 at 50, 70, 90, 110, and 130 A degrees C are estimated using the Semenov equation. At 130 A degrees C, the storage life of CL-20 is extrapolated to 18.14 h, 8.20, 21.22, and 27.30 days, while taking the reaction extents of 1, 2, 3, and 4%, respectively, as the end points of life. These values correspond to the values obtained in the present work.