The invention provides a nanocrystalline accumulation meso-microporous ZSM-5 catalyst and preparation and application thereof. The catalyst is aggregated by small grains with particle sizes of 20-100 nm to an aggregation state with a particle size of 200-2000 nm, the aggregation state forms the catalyst, the specific surface area of the catalyst is 350-420 m<2>/g, and the pore volume of the catalyst is 0.25-0.35 cm<3>/g. According to the invention, a mesoporous-microporous composite nanocrystalline accumulation state ZSM-5 molecular sieve is directly synthesized; under the condition of adding no second template, a solid silicon source is pretreated to generate different degrees of depolymerization, the material ratio of the synthesis system is further adjusted, a sodium salt is added to adjust the growth speed in a crystallization process of the molecular sieve, and meanwhile, a two-stage crystallization method is adopted to promote the generation of a crystal nucleus at a low temperature and promote the growth of a crystal at a high temperature, so as to synthesize a serial grain aggregation state ZSM-5 molecular sieve.