In this article, a series of mathematical and physical models for the adsorption of biomacromolecules are established. As shown, the adsorption of biomacromolecules is actually considerably complicated and often involves various interactions, such as electrostatic, hydrophobic, and hydrogen-bonding, etc. Considering this, these models show that if these interactions are heavily involved in the process, the plot of ln Q (or Q) vs ln C* is normally expected to be a straight-line. Otherwise, if the linearity exists between C*/Q vs C*, the adsorption would be an ideal process without the intervention of them. Meanwhile, this article also presents corresponding relationships for the adsorption in multisited binding and multilayer forms. Other aspects including ion-exchange systems are also discussed (C*, the equilibrium concentration of biomacromolecules; Q, the adsorbance).