Embodiments of this application provide a policy update method and apparatus. The method includes obtaining, by a policy control network element, updated policy information of a local area data network (LADN), and sending, by the policy control network element, the updated policy information and instruction information to an access and mobility management network element. The instruction information is used to instruct the access and mobility management network element to regionally update the updated policy information. According to the embodiments of this application, signaling overheads of the LADN in a policy update process are reduced.