To gain confidence in safety-critical interactive systems, formal modelling and analysis plays a vital role. The aim of this paper is to use Coloured Petri Nets to model and analyze safety-critical interactive systems. We present a technique to construct a single Coloured Petri Net model of the user interface, interaction and functionality of safety-critical interactive systems and then analyze the achieved Coloured Petri Net model using a state space analysis method. There are several reasons for using Coloured Petri Nets. Coloured Petri Nets provides a graphical representation and hierarchical structuring mechanism, and a state space verification technique, which allows querying the state space to investigate behaviours of a system. There are several tools that supports Coloured Petri Nets including the CPN Tool which helps in building CPN models and allows simulation and analysis using state spaces. The technique to model and analyze safety-critical interactive systems is illustrated using a simplified infusion pump example.