A roaming method for a mobile terminal in a wireless local area network is disclosed. In the method, a target access point (AP) device receives an access request for roaming from the mobile terminal, and a target access controller (AC) obtains mobility information of the mobile terminal in an original extended service set based on the access request, wherein the mobility information include information of an AP device, an AC and a mobile agent server associated with the mobile terminal. Then the target AC determines whether the roaming for the mobile terminal is an inter-IP subnet roaming or an intra-IP subnet roaming based on the obtained mobility information. The target AC performs mobile IP based handover when the roaming is determined as the inter-IP subnet roaming and performs Inter Access Point Protocol based handover when the roaming is determined as the intra-IP subnet roaming.