A display apparatus and a power control method thereof are provided. The display apparatus includes a power supplying part; a Transition Minimized Differential Signaling (TMDS) receiving part which decodes a TMDS signal input from an external signal source; a controller which controls the power supplying part to supply driving power to the TMDS receiving part when a clock signal of the TMDS signal is received. The power control method includes cutting off driving power to a Transition Minimized Differential Signaling (TMDS) receiving part when the display apparatus enters a power-saving mode; determining whether a clock signal is detected in a TMDS signal; and supplying driving power to the TMDS receiving part if it is determined that the clock signal is detected.