To have a fundamental understanding on the principle of carbon aerogels when it is used as electrode materials in power battery, the effects of density and structural properties on the electrical conductivity of carbon aerogels was investigated in this paper. Carbon aerogels with different density were prepared via adjusting the chemical conditions of the primary solution. The morphology of carbon aerogels were observed by field emission scanning electron microscopy (FE-SEM). Experimental results show that the electrical conductivity of carbon aerogels is ranged from 10-6 Ω/cm to 10 Ω/cm, and that not only the density but also the carbon particle size and porosity of carbon aerogels effect the transport property greatly. With the increasing of the density the electrical conductivity of carbon aerogels increases. This indicates that larger particle size and lower porosity of the nano-structure lead to higher conductivity.