Nanometer ZSM-5 molecular sieve catalyst with high silica-alumina ratio and preparation method thereof

The invention relates to the field of materials and catalysts, and provides a nanometer ZSM-5 molecular sieve catalyst with a high silica-alumina ratio. The nanometer ZSM-5 molecular sieve catalyst has an appropriate nano particle size and a high silica-alumina ratio, wherein the nano particle size is in the range of 0.1nm to 500nm; the molar ratio of SiO2 to Al2O3 is not less than 30; and micropores 0.5-2nm in diameter are arranged in a molecular sieve. An organic template method is adopted; organosilane is directly added into an original solution of the molecular sieve and silane is grafted onto a ZSM-5 molecular sieve seed crystal under the conditions of condensation and backflow; and a product is roasted to remove an organic template and the organosilane. By adopting the invention, synthetic steps are simplified, the synthetic method is simple, the cost is low and the application prospect is wide.