An OLED (Organic Light-Emitting Diode) display device and a pixel circuit thereof are disclosed. In a pixel circuit, a driving transistor driving an OLED is controlled for a reset operation and a compensation of the pixel circuit, by which a threshold voltage of the driving transistor is memorized on a control terminal of the driving transistor. In the compensation operation, a connection node between the driving transistor and the OLED is specially controlled. A switch circuit is provided in the pixel circuit. Based on a control signal, the switch circuit couples the connection node to a control voltage level. An enable interval of the control signal covers an enable interval of the reset operation and an enable interval of the compensation operation.