A non-blocking supervisory control problem to meet bounded time constraints for non-deterministic real-time discrete event systems (DESs) is addressed. To this end, notions of trace controllability and time controllability are introduced for the non-deterministic real-time DESs with respect to a timed language specification representing a bounded time constraint. The existence conditions of a non-blocking supervisor to achieve the timed language specification are presented on the basis of the proposed notions, and these are further illustrated by an assembly work station example.