The present application provides a displaying device and a controlling method thereof, which relates to the technical field of displaying. The displaying device can solve the problem of residual images generated in power-off and greatly improve the product quality and the user experience. The displaying device includes: a time-sequence controlling circuit, a power-supply circuit, a system controlling circuit and a display panel; the power-supply circuit is electrically connected to the time-sequence controlling circuit and the system controlling circuit, and is configured for: providing a first power-supply voltage and a second power-supply voltage to the time-sequence controlling circuit, wherein a magnitude of the first power-supply voltage and that of the second power-supply voltage are different; in a normal shutdown mode, under control of the system controlling circuit, firstly shutting down an output of the first power-supply voltage, after a first time period, shutting down an output of the second power-supply voltage.