The invention discloses a pixel driver circuit and driving method thereof. The pixel driver circuit comprises a first TFT (T1) connected to first node (G) and second node (K); a second TFT (T2), connected to first control signal (S1), first node (G) and second node (K); a third TFT (T3), connected to second control signal (S2) and second node (K); a fourth TFT (T4), connected to first control signal (S1), third node (N) and reference voltage (Vref); a fifth TFT (T5), connected to first control signal (S1), third node (N) and data signal (Vdata); a sixth TFT (T6), connected to third control signal (S3); a first capacitor (C1) and a second capacitor; the reference voltage (Vref) being less than data signal Vdata). The invention also provides a corresponding driving method. The invention uses internal detection to eliminate luminance inconsistency caused by change of the driving TFT threshold voltage.