Microflotation tests were performed on such pure minerals as diaspore and kaolinite to detect their respective flotation behaviors and flotation selectivity, in which 20 quaternary ammonium salts were applied as collectors to explore the relationship between the structure and selectivity of quaternary ammonium salt so as to investigate the probability of application of QSAR in the development of flotation reagents. Based on the selection and calculation of quantization parameters, topological parameters and selectivity indices of the reagents, a model with robust predictive abilities was established. The results showed that the shape of molecule, total energy and hydrophobic property were the three major factors affecting the selectivity of collectors. The better matching degree of molecular chain length and molecular configuration and the more negative total energy of the reagent were, the more efficient the reverse flotation separation of aluminum-silicate minerals would be. (C) 2011 Elsevier Ltd. All rights reserved.