Embodiments of this application provide a wireless communications method and device to implement an inter-system network handover in the case of flexible registration modes of a terminal device. The method includes: determining, by a first network device in a first system, a registration mode and/or a supported registration mode of a terminal device, where the registration mode is a single registration (SR) mode of registration with a single system or a dual registration (DR) mode of registration with dual systems, and a first cell in the first system is accessed by the terminal device; and determining, by the first network device according to the registration mode and/or the supported registration mode of the terminal device, a procedure that needs to be performed or cannot be performed for the terminal device to access a second cell in a second system.