A method and a system for controlling data response with the aid of at least one attribute of a transaction identifier (ID) are provided. The method includes: transmitting the at least one attribute in conjunction with the transaction ID from any master device within one or more master devices to a slave device; and according to the at least one attribute, determining whether to utilize a specific data path among multiple data paths for sending response data corresponding to the transaction ID from a memory device within the slave device to the aforementioned master device. More particularly, the specific data path is a data path having maximum transmission efficiency among the multiple data paths.