A video processing apparatus and a control method thereof are provided. The video processing apparatus includes: a processing unit which processes a video signal for display; a clock generating unit which generates a system clock for driving the processing unit and outputs the system clock to the processing unit; a power supply unit which supplies power to the processing unit; and a controller which counts a power supply time using a clock generated from the system clock. The controller compares the counted power supply time with a predetermined reference time, and controls power supplied to the processing unit from the power supply unit.