A handoff method in a wireless local area network (WLAN) and an apparatus using the same are provided. A mobile station (MS) switches between a data transceiving mode and a probing mode at a predefined interval when the MS is transmitting/receiving packages. In the probing mode, the MS probes one or more channels each time and selects an access point (AP) for handoff from the probing result according to a predetermined rule, so as to re-establish a network connection.