Organic light-emitting diodes (OLEDs) have attracted a great deal of attention due to their potential application in full-color displays and illuminations. For commercial applications, the operation stability of OLEDs is of essential concern. As the carrier transport in amorphous organic semiconductor is the repeated redox of the molecules, the electrochemical property of the materials is an important factor correlated to the operational stability of OLEDs. In this review, we present the study on the electrochemical property of stable OLED materials in recent years. Ambipolar transporting materials with stable cations and anions will be highlighted.