A method for sending packet data is provided, which includes the following steps. Packet data from a source mobile station (MS) is received. The packet data includes an identity of a destination MS. A routing cache table is searched for a path to the destination MS. An interface is selected if the path to the destination MS is found. The packet data is forwarded through the selected interface according to the found path. Other two methods for sending packet data corresponding to the method for sending packet data as well as an MS and a base station (BS) corresponding to the method for sending packet data are provided. Therefore, link processing can be performed at the MS.