A pixel circuit includes a liquid crystal capacitor, a selection unit, a gray scale writing unit, and a reset unit. The selection unit is configured to determine whether to charge the liquid crystal capacitor according to a row control signal and a column control signal. The gray scale writing unit is configured to apply a gray scale voltage signal to the liquid crystal capacitor, when the selection unit determines to charge the liquid crystal capacitor, and an application duration of the gray scale voltage signal controls a gray scale level displayed by the liquid crystal capacitor. The reset unit is configured to disconnect the gray scale writing unit and the liquid crystal capacitor to stop charging the liquid crystal capacitor upon receiving the reset signal, and reset the voltage of the liquid crystal capacitor to an initial state.