The invention discloses a method and a system for switching an emergent session. The method comprises the following steps that: user equipment and/or a source access network save address information of grouped data gateway used for emergent bearer establishment in a process of emergent bearer establishment between the user equipment and a source access system; when the user equipment is determined to be switched to a target access system, the target access system acquires the address information of the grouped data gateway saved in the user equipment or the source access system; and the target access system establishes emergent bearer according to the address information and the grouped data gateway to realize switching of emergent session. According to the technical scheme disclosed by the invention, the success switching of the emergent session of the UE without a SIM card can be ensured.