The power line communication (PLC) channel has been a transmission medium that enables to transfer high-speed digital data through the classical electrical wires. Channel characteristics of power lines are very important for communications systems design. In order to get the suitable model for power line communications analysis and improve the PLC communication quality, researchers do lots of study about the PLC channel characterizations based on actual measurement and theoretical analysis. This paper reviews the conclusions of recent studies, summaries the characteristics of PLC channel for medium voltage power lines and low voltage power lines. The further research is also put forward.