Reaction dynamics on multiple electronic surfaces have been studied by performing quantum scattering calculations on a collinear A+BC --> AB+C reaction. We propose model diabatic potentials with variable coupling potentials to examine the effect of the coupling between electronic states on the reaction. Time-independent quantum scattering theory based on diabatic representation provides a useful framework for treating reaction dynamics on coupled electronic states. Reaction probabilities calculated from the diabatic approach intrinsically include the effect of the presence of the excited state. We compared the results from the two-surface diabatic calculations with those using the single adiabatic surface alone. By varying the strength and the range of the diabatic coupling potential, we obtained a wide spectrum of reaction models. It is found that the reaction probabilities from the two-surface diabatic calculations showed noticeable differences from the single-surface adiabatic case. These results demonstrate that the effect of the excited states cannot be ignored even though the two electronic states are well-separated in energy.