Mutual interactions of ionic polymer with ionic surfactant on alumina surface in system PAA/SDS/Al₂O₃/NaCl solution system were studied. The research was preceded by studies of the polymer and surfactant in aqueous solution. Obtained data were used for explanation of adsorption equilibrium in the alumina - polymer solution system in SDS presence. Mechanism of polyacrylic acid - surfactant interaction on Al₂O₃ was explained basing on adsorption and surface tension changes measurements of pure and mixed PAA and SDS solutions in studied system. An influence of the polymer molecular weight and surfactant concentration on adsorption equilibrium at metal oxide- polymer-surfactant interface was considered. An essential role of carboxyl groups of the polymer chain was proved in these systems.