The present application discloses a method, device, and system for selecting a user plane functional entity supporting non-3GPP access ensure service continuity. When a user equipment (UE) performs access via a 3GPP network, subscription data of the UE are obtained by a CP functional entity. The subscription data include indication information that indicates whether the UE is allowed to connect to a non-3GPP network. If the indication information indicates that the UE is allowed to connect to the non-3GPP network, a target UP functional entity supporting the non-3GPP access is selected by the CP functional entity. The present application is applicable to the field of communications technologies.