To explore the desorption behavior of polymers from the solid surfaces, a new experimental technique was introduced in this research. We referred to it as the "continuous elution method". Using this method, the desorption behavior of preadsorbed polystyrene (PS) and polystyrene (PS-X) functionalized by a terminal iminium ion (X) from alpha- and gamma-alumina surfaces was investigated. The particles preadsorbed by PS or PS-X were packed into a small column and eluted by various solvents. Irreversibility of polymer adsorption can be observed clearly, the adsorption/desorption amount can be determined, and much new information on kinetics of desorption, adsorption energy, solvency effect, and etc. was also obtained. On alpha-alumina, it was found that only the X-group is the driven force for adsorption, and the adsorbed layer has a higher energetic state than that on gamma-alumina. A complicated desorption kinetics of polymer desorbed from gamma-alumina was observed, which has a relation to the porosity of adsorbent.