The invention discloses a hierarchical pore ZSM-5 molecular sieve with a nanosheet layer structure and a synthesis method thereof; the hierarchical pore ZSM-5 molecular sieve with the nanosheet layer structure is formed by cluster stacking of nanosheet layers with the thickness of 30 to 50 nm; an amphiphilic cationic surfactant is used as a structure directing agent, potassium hydroxide or sodium hydroxide is used as an alkali source, a synthesis solution with the molar ratio of (20-100)SiO2:(0.4-3)Al2O3:(10-50)ROH:(1000-3000)H2O:(1-10)SDA is prepared and then is subjected to hydrothermal crystallization according to a conventional method, and the product is washed, dried and roasted to obtain the ZSM-5 molecular sieve. The molecular sieve is the hierarchical pore ZSM-5 molecular sieve having the nanosheet layer structure and formed by self assembly of the amphiphilic cationic surfactant and an inorganic species through interaction, has the characteristics of large specific surface area, short diffusion path and good stability; and the preparation method has the advantages of high degree of crystallinity and simple operation.