Electrical conductivity measurement for the detonation product is put forward by means of measuring the electrical conductivity of detonation product for the composite explosive composed of HMX and TNT. Experimental results indicate that the electrical conductivity of aluminized explosive is obviously higher than that of the explosive without aluminium. TNT′s (density 1.520 g·cm^-3) maximum electrical conductivity is 18000 Ω^－１·m^－1. The electrical conductivity of TNT 80/Al 20（density 1.628 g·cm^-3）is 1.136×10⁷ Ω^－１·m^－1. It is concluded that the explosion temperature and electron concentration increase with aluminum powder appended in the same explosion,which results in the increasing electrical conductivity of detonation product by the calculation of explosion temperature and electron concentration for detonation product.