The adsorption and desorption behavior of protein human serum albumin (HSA) on magnetic polymer particles covered by thermosensitive polymers was investigated. The results showed that adsorption was dependent mainly on the properties of the particle surface. By increasing the temperature, particles deswelled and were susceptible to absorb larger amounts of proteins, which could be desorbed at lower temperature. The extent of adsorption was found to depend on the pH value, protein concentration, and incubation time. At higher pH, a smaller amount of proteins could be absorbed because of the electrostatic repulsive force between the protein and the surface particles. Increasing incubation time or initial protein concentration was favorable to the adsorption of proteins.