A method is developed for predicting the zone-sharpening effect in linear gradient- and stepwise-elution chromatography of proteins. Numerical calculations have shown that the elution curve by different models are almost the same when the values of zone spreading parameters in the model are chosen so that the values of the number of the theoretical plates are equal. A good correlationship curve is established on the basis of the numerical calculations, from which the degree of the zone-sharpening can be easily predicted with a single dimensionless parameter.