Abstract: The shelf-life of 10% sodium phenobarbital injection(containing propylene glycol 60%) has been predicted by accelerated stability test with the classical isothermal method (at 100, 90, 80 and 70℃). The data was treated with regressive calculation, and the shelf-life calculated with three different methods (regressive calculation, average activation energy calculation and graphical plotting).The values obtained from these three methods were approximately equal, and also coincided with the value obtained from samples reserved for observation at room temperature. The shelf-life was 1.05 years at 25℃, and 2.03 years at 20℃.