The present invention discloses an interface transmission method including: enabling a first command string including a first sub-command to be transmitted to a storage device from a processing device during a first period; enabling a second command string including a second sub-command to be transmitted to the storage device from the processing device during a second period, wherein the first sub-command and the second sub-command constitute a command; when the command is a write command, enabling a write data string to be transmitted to the storage device from the processing device during a third period, wherein the write data string includes write data; and when the command is a read command, enabling a read data string to be transmitted to the processing device from the storage device during the third period, wherein the read data string includes read data.