  We develop an approach to realize a quantum switch for Rydberg excitation in
atoms with $Y$-typed level configuration. We find that the steady population on
two different Rydberg states can be reversibly exchanged in a controllable way
by properly tuning the Rydberg-Rydberg interaction. Moreover, our numerical
simulations verify that the switching scheme is robust against spontaneous
decay, environmental disturbance, as well as the duration of operation on the
interaction, and also a high switching efficiency is quite attainable, which
makes it have potential applications in quantum information processing and
other Rydberg-based quantum technologies.
