Abstract: A multi-memory collaboration structure based on SPI interface is provided, including a first memory, a second memory, and a control module. In an embodiment, instruction codes of first actuating commands transmitted from the control module to the first memory are different from those of second actuating commands transmitted from the control module to the second memory. In another embodiment, a first actuating command has a preselected instruction code and an alternate instruction code, and a second actuating command has a second instruction code, wherein the preselected instruction code is different from the alternate instruction code, and at least one of the preselected instruction code and the alternate instruction code is different from the second instruction code. Therefore, the invention only requires one chip select port to avoid signal conflict between different memories, thereby effectively reducing the fabrication costs.