A storage control system, for controlling data transmission between a computer and an external device, includes a USB interface connected to the computer, an external interface connected to the external device and a control module connected between the USB interface and the external interface. The control module includes a data transmission submodule transmitting data with the computer, a microcontroller controlling a work flow of the control module, a ROM connected to the microcontroller, a protocol resolution submodule resolving data, a protocol timing sequencer connected to the external interface for transforming protocols and a buffer connected between the protocol resolution submodule and the protocol timing sequencer for storing data. The ROM changes its code according to different external devices. The microcontroller controls a work flow of the control module according to the code of the ROM to realize functions of different external devices. The invention further provides a storage control method.