γ-Fe2O3@SiO2-linker-L-Leucine as a new type of recoverable superparamagnetic nanocatalyst was prepared for the first time. The catalyst was identified and its acidity was measured by potentiometric titration through reverse titration method. The activity of catalyst was investigated in the three-component one-pot reaction of arylglyoxal monohydrate, cyclic 1, 3-dicarbonyls and thiobenzamide derivatives in water. The catalyst showed effective catalytic activity for the preparation of a wide range of thiazole derivatives using this green protocol. After the reaction, the catalyst is easily separated by an external magnetic field. The catalyst was used at least five times without losing its high catalytic activity.