An OLED pixel circuit and a display apparatus comprising the OLED pixel circuit. An OLED pixel circuit comprises an OLED and driving units (TFT1, S1, C) for driving the OLED to emit light, wherein one electrode of the OLED is connected to the driving units (TFT1, S1, C). The OLED pixel circuit further comprises compensation units (R1, S2, TFT2, R2). The compensation units (R1, S2, TFT2, R2) comprises a sensing element (R1) which can sense light and convert an optical signal of the OLED into an electrical signal. The compensation units (R1, S2, TFT2, R2) compensate for currents used by the driving units (TFT1, S1, C) to drive the OLED according to the light-emitting brightness of the OLED.