Disclosed are a main image processing apparatus, a sub image processing apparatus and a control method thereof. The control method of the sub image processing apparatus includes receiving a user's touch input through the sub image processing apparatus; determining which contents correspond to a touched area where the touch input occurs; sensing change in location of the touch input; and transmitting a control command for the contents to the main image processing apparatus in response to the sensed change in the location of the touch input. With this, it is more convenient for a user to control the main image processing apparatus through the sub image processing apparatus supporting the touch input.