Abstract: A driving circuit for an OLED includes: a first TFT (T1), a second TFT(T2), a third TFT(T3), a fourth TFT(T4), and a first capacitor (C1). The fourth TFT is added to the present driving circuit based on the conventional 3T1C driving circuit. Benefits of the design are no influence of the threshold voltage, improvement of uniformity and stability of the electric current of the OLED, and improvement of display quality of the OLED. Besides, a data signal is only switched between signals with two different electric potentials, which efficiently solves the problem that a data signal of the conventional driving circuit is switched among signals with three different electric potentials in a cycle while it is hard to realize to switch among signals with three different electric potentials in a cycle.