In object-oriented systems development, a lifecycle model and an interaction model are generally adopted in the specification of object behaviour. This specification by two separate models is liable to the problem of inconsistent specification between object lifecycle and interaction. In this paper, we propose an approach to deriving scenarios of object interaction through a Petri net which is directly constructed from the lifecycle models of the interacting objects. The proposed approach offers an effective mechanism for deriving scenarios of object interaction without separately constructing an interaction model, and more important, encourages consistent specification between object lifecycle and interaction.