Cyber-Physical Systems (CPSs) have great potentials in several application domains. Time plays an important role in CPS and should be specified in the very early phase of requirements engineering. This paper proposes a framework to model and verify timing requirements for the CPS. To begin with, a conceptual model is presented for providing basic concepts of timing and functional requirements. Guided by this model, the CPS software timing requirement specification can be obtained from CPS environment properties and constraints. To support formal verification, formal semantics for the conceptual model is provided. Based on the semantics, the consistency properties of the timing requirements specification are defined and expressed as CTL formulas. The timing requirements specification is transformed into a NuSMV model and checked by this well-known model checker.