Dynamic simulation is used to understand the effect of a startup policy on the ethyl tert-butyl ether (ETBE) reactive distillation. Because input multiplicity is likely to occur in every reactive distillation, its effects on startup are investigated. The ETBE reactive distillation is presented as an example to show characteristic behaviors during startup of the ETBE column, It is found that the dynamics of the startup condition are influenced by the given startup policy. An understanding of the input multiplicity is a necessary requirement before performing the startup operation to avoid excessive energy, to achieve a stable optimum process operation.