A command transforming method, applied to a command transforming system comprising a first transceiving interface and a second transceiving interface, comprising: receiving at least one command transmitted from a first device via the first transceiving interface; determining a first sequence rule of the first device and a second sequence rule of a second device, wherein the first sequence rule means if the first device is required to process the command in sequence and the second sequence rule means if the second device is required to process the command in sequence; transmitting the command to the second device via the second transceiving interface; processing the command by the second device according to the second sequence rule and transmitting a response corresponding to the command to the second transceiving interface by the second device; and transmitting the response to the first device according to the first sequence rule.