Embodiments of the present invention disclose a method and an apparatus for service offloading between different networks. By means of capability negotiation between an ANDSF unit and user equipment, a network side controls the user equipment to send an ISRP request to the ANDSF unit; a non-3GPP network is accessed by using an instruction, generated by the ANDSF unit according to the ISRP request, for instructing to access the non-3GPP network; and after the UE is simultaneously connected to a 3GPP network and the non-3GPP network, services of the user equipment that camp on the 3GPP network and services of the user equipment that camp on the non-3GPP network are indicated according to an ISRP offloading policy that is delivered by the ANDSF unit according to the ISRP request.