This paper discusses a scenario-based scheme to address process operation problems under variations. As an illustration, two typically encountered problems, a short-term operation planning problem and a long term supply chain planning problem, are investigated considering the effect of variations. Their mathematical programming models explicitly reflecting the variations in the form of multiple scenarios with their probabilities are presented to provide robust decisions in the face of variations. It is hoped that the proposed framework can be a reminder of the importance of the scenario-based approach in the current uncertain business circumstances.