A method for transmitting subframe grouping information is provided. The method includes updating a grouping information field of a media access control (MAC) message, which a serving base station periodically broadcasts to a mobile station (MS), using subframe grouping information determined by a target base station, and periodically transmitting the MAC message to the MS. The method provides downlink signaling for supporting variable Transmission Time Intervals (TTIs) of a base station when handover is performed, thereby minimizing service delay of each mobile station and enabling efficient utilization of resources.