The change of an initiating device′s function time was studied by accelerated life test at 60 ℃, and relative humidity 95%. Results show that the mean value of the detonator′s single function time prolongs when the time of life test continues. And at the ageing time of 0, 21, 35 and 45 days, the maximum value of function time and the ageing time have good linear relatiouship. The reliability value of the tested sample falls to 98.98% when the ageing time is 56 days, and falls to 15.06% when the ageing time is 67 days.