A combination apparatus capable of data communication between host devices and a data communication method thereof are provided. The combination apparatus includes a first host device that controls a first function block to perform a first function, a second host device that controls a second function block to perform a second function, and an advanced technology attachment (ATA) adjuster that performs a data communication between the first host device and the second host device through an ATA packet interface. Accordingly, the data communication is more effectively performed between the host devices.