Organo-clay chemistry is the discipline that study the interactions of clay minerals and organic compounds, which include adsorption of organic compounds on the clay minerals and the catalytic effect of clay minerals on the transformation of organic compounds on clay surfaces, and as well as the effect of organic compounds on the formation and weathering of clay minerals. This paper stressed the importance of the organo-clay chemistry in soil science, environmental protection, drilling industry,chemical engineering, petroleum exploration, and reviewed the progress in the research in this area during the last two decades. The synthesis of organo-clay complexes can be reached through the reaction of melted organic compounds with clay, grinding method, polymerization of previously adsorbed monomers,
exchanging an easy intercalated compounds, in additon to the traditional direct solution-suspension reaction. The general bonding mechanisms and steric orientation of simple organic compounds on clay surfaces and in the interlayers of swelling minerals are clearly understood. Clays modified with quaternary
ammonium containing long alkyl chains can tremendously increase their removal capacity for hydrophobic organic contaminants such as oil and aromatic compounds from water. Clay minerals can function as Bronsted and Lewis acid catalyst in the transformation of organic compounds; pillared clays, which are
intercalated with polyoxymetal cations in the interlaysers of smectite, can play the same roles as molecular sieves, which can increase the selectivity or specificity of the reactions. Clay minerals have been used in many reactions such as petroleum cracking, dehydration, esterification, transamination, epoxydation, and
so on. The catalysis of clay minerals may play important roles during petroleum formation. Clay minerals also influence some biochemical processes by their adsorption or catalytic effects, such as the synthesis and polymerization of aminoacids, the biochemical activity of nucleoside, nucleotide, enzyme cofactor and enzyme. These effects imply the clay minerals may have had their role in chemical evolution on the early earth. Further-going research will extend the minerals from currently mostly studied smectite to more clay minerals, and from simple model organic compounds to more complicated compounds such as humus materials. Future studies should pay more attention to the roles of clay mineral in the transformation of organic compounds in the complex soil and sediment systems. The role of clay mineral in the chemical evolution of early Earth which lead to the origin of life will be studied by organo-clay scientists in the future.