Multistage porous molecular sieve catalyst and preparation method thereof

The invention discloses a multistage porous molecular sieve catalyst and a preparation method thereof, and belongs to the technical field of waste plastic resource utilization and cleaning vehicle fuel production. The catalyst comprises 30-70wt% of a microporous structure-containing micro-mesoporous composite MCM-41 molecular sieve, 0.5-3.0wt% of La2O3, 0.5-5.0wt% of P2O and the balance a binder. The preparation method of the catalyst comprises mixing the molecular sieve, the La2O3 precursor, the P2O5 precursor, an alumina precursor, clay and water, carrying out uniform slurrying, wherein a ratio of total raw material dry base mass to water mass is (0.2-0.6): 1, carrying out spraying molding and carrying out roasting to obtain the catalyst. The catalyst is used for catalytic conversion of a polyolefin macro-molecule raw material and has the characteristics of high catalyst active site utilization rate, good diffusion and mass transfer performances, good hydro-thermal stability and good regeneration performances.