The influence of electron injection on the electric-pulse-induced resistive switching of perovskite CaCu3Ti4O12 (CCTO) films was studied by current-voltage (I-V) measurements. The electron injection was reduced by annealing the sample in an O-2 atmosphere. The switching from the high-resistance state HRS to the low-resistance state LRS by a filamentary mechanism was suppressed when the carrier injection occurs by Poole-Frenkel emission. The interfacial potential barrier plays a crucial role in determining the carrier injection. (C) 2011 Elsevier B.V. All rights reserved.