We investigated the space charge behavior near the interface between different low-density polyethylene (LDPE). Charge carriers were mainly injected from the semiconductive electrode in a specimen of Al/LDPE/LDPE/semiconductive layer and they moved through the interface to the counter Al electrode. Charge carriers moving from a lower density LDPE to a higher density one were accumulated near the interface to form space charge, while there was no space charge accumulation for carriers moving in the opposite direction. The mobilities of charge carriers were estimated from the change in space charge profile with time. Charge carriers are more mobile in the lower density LDPE than in the higher density one. Positive carriers were more mobile in LDPE than negative ones. The interface between different LDPE's greatly affected space charge behavior and discharging currents.