A portable terminal having a mass storage secondary memory and a method for the portable terminal, wherein high-speed data transfer between the mass storage secondary memory and an external apparatus is supported in a multitasking manner are provided. Between the portable terminal having the mass storage secondary memory and the external apparatus, the method of setting a data transfer path comprises setting a first data path so as to permit the mass storage secondary memory to operate according to internal control of the portable terminal, determining whether the portable terminal is connected with the external apparatus through a USB switcher, and if the portable terminal is connected with the external apparatus, determining whether a set command is input to set the mass storage secondary memory as a portable disk of the external apparatus. If the set command is input, the first data path is blocked, and a second data path is set to permit the mass storage secondary memory to operate according to external control exercised by the external apparatus. The portable terminal can perform a task operation in a multitasking manner independently of the ongoing data transfer between the mass storage secondary memory and the external apparatus, and high-speed data transfer between the mass storage secondary memory and the external apparatus is possible through a high-speed USB interface.