The present invention relates to an LBO service support method and system in a wireless communication network including femtocells. The LBO service support method according to the present invention comprises: a first step in which a terminal connected to a femtocellsbase station transmits a PDN connection request message including identification information of the terminal to a mobility management entity via a femtocell base station gateway, for forming a bearer with a femto PDN gateway connected to an LBO network; a second step in which the mobility management entity transmits a bearer creation request message to a femto serving gateway having the same location information as the femtocell base station gateway, for forming an LBO bearer; a third step in which the femto serving gateway acquires location information of the femto PDN gateway by using the identification information of the terminal; and a fourth step in which the femto serving gateway forms an LBO uplink bearer or LBO downlink bearer by using the location information of the femto PDN gateway.