Embodiments of the present invention disclose a capability determining method for a terminal device, a capability configuration method for a terminal device, a host, a terminal device, and a system. The capability determining method for a terminal device includes: acquiring, by the host, a capability supported by the terminal device; determining, by the host according to the capability supported by the terminal device and a capability supported by the host, a capability supported by both the terminal device and the host, and using the capability supported by both the terminal device and the host as an overlapping capability, where the overlapping capability is used by the terminal device to perform capability configuration; and sending the overlapping capability to the terminal device. The embodiments of the present invention resolve a problem that because capabilities supported by a host and a terminal device are not exactly identical, the host cannot perform flexible configuration on the terminal device acc
