A booting method of a digital processing having a first processor and a second processor is provided. An interface between the first processor and the outside is stopped. A second processor program code is transmitted to a second memory from a first memory. A second stage loader (SSL) for the first processor is transmitted to a buffer of the second processor from the first memory. A first processor program code is transmitted to the second memory from the first memory under the control of the second processor and an interface between the first processor and the outside is resumed. The first processor program code is downloaded fast into the second memory to decrease booting time of the digital processing system.