An OLED driving compensation circuit and a driving method thereof are provided. The circuit comprises an external compensation module and a driving module comprising a driving transistor and a storage capacitor. The driving transistor is respectively connected with a power supply voltage terminal and an OLED via a first electrode and a second electrode thereof, a first terminal of the storage capacitor is connected with a control electrode of the driving transistor, and a second terminal thereof is connected between the driving transistor and the OLED. The external compensation module is connected between the driving transistor and the OLED and provides a reference voltage to the electrode of the driving transistor connected with the second terminal of the storage capacitor, to reset the voltage on the electrode. The power supply voltage terminal as variable voltage source inputs a first voltage equal to the reference voltage when the voltage is reset.