The composite of nano-SiOx and low-density polyethylene is prepared with the double-solution method. Space charge distribution in the composite with various nano-SiOx contents is carried out by pulsed electro-acoustic method. It is shown that the amount of space charge in the composite increases with the nano-SiOx content. The space charge in the composite under 50 kV/mm dc stress is mainly hetero, which is very different from that in the pure polyethylene. However, after electrically stressed at 50kV/mm for one hour, homo space charge is found while the composite being short-circuited. It is believed that the homo space charge injects and accumulates during the dc stressing process, which mainly contributes to the formation of the space charge