The invention provides a pixel circuit and a driving method thereof, a display panel and a display device. The pixel circuit comprises eight transistors, two storage capacitors and an organic light emitting device (OLED), a threshold voltage of the first transistor is compensated through mutual cooperation of the transistors and the capacitors, a driving current for driving the OLED to emit lightis made to be independent of the threshold voltage of the first transistor, so influence of fluctuation of the threshold voltage of the first transistor on the OLED is avoided, a problem of uneven display brightness caused by this is solved, the display effect of the whole frame is improved, moreover, since the leakage current between the first storage capacitor and the second storage capacitor can be reduced by the eighth transistor, reduction of a gate voltage of the first transistor is avoided, a problem of scintillation caused by the leakage current is solved, and the display effect of thewhole display frame is further improved.