To investigate the effects of temperature on the electrical explosion and ignition of semiconductor bridge （SCB）， the electrical explosion characteristics and ignition performance of SCB with the ambient temperature of 25 ℃ and -40 ℃ were studied by a capacitive discharge method， and a mathematical model was established. The ignition temperature of Al/CuO nanothermite was tested at ambient temperature of 25 ℃ and -40 ℃， respectively. The ignition sensitivity of SCB was measured by the D-optimization method. When the charging voltage increases from 30 to 50V， the difference of critical initiation time reduced from 0.47 to 0.25 μs. The difference of critical initiation energy increased from 0.16to 0.65 mJ. Results shown that with the increase of charging voltage， the influence of ambient temperature on the critical initiation time decreased， and the influence on the critical initiation energy increased. Both the ignition temperatures of Al/CuO nanothermite at 25 ℃ and -40 ℃ are 740.7 ℃. The 50% ignition voltage at ambient temperature of 25 ℃ is 0.6 V lower than that at -40 ℃.