A display device and a pixel circuit thereof. The pixel circuit generates threshold voltage information of a driving transistor (21) in a source following manner, a threshold voltage of the driving transistor (21) and a reference voltage related to gray scale information are generated at two ends of a first capacitor (26) by means of voltage division of the first capacitor (26) and a second capacitor (27), and the reference voltage keeps unchanged during a light-emitting process, so that a driving current flowing through a light-emitting device (25) is irrelevant to threshold voltages of the driving transistor (21) and the light-emitting device (25), thereby compensating the threshold voltage deviation of the driving transistor (21) and the light-emitting device (25), and solving the problem of nonuniform display. When the display device emits light line by line, the display device reduces the line programming time of the circuit by overlapping scanning signals and control signals, so that the demands for high-resolution and high-frame-frequency display panels are met while high precision is obtained. When the display device emits light in a concentrated manner, the pixel circuit reduces the complexity of the circuit and increases the light-emitting time by means of grouped programming and grouped light emission.