The quasi-lognormal distribution (Q-LND) probability density function and its integrating form (Q-LND approximation) were used to predict linear chromatographic elution curves and breakthrough curves, respectively. By comparing with the exact solution of the breakthrough curves, a general criterion for the applicability of the Q-LND probability density function and its integrating form was provided. The equations that include the first absolute moment and the second central moment were presented to calculate the chromatographic figures of merit for ideal and asymmetry peaks. Some problems such as the volume overloading in linear chromatography were discussed.