The invention relates to a beta zeolite particle with multistage openings, the mole ratio of SiO2/ Al2O3 being 80-120, the mean particle size being 0.1-0.5um, opening capacity being 0.35-0.50ml/ g, and aperture collectively distributing at three-stage 0.1-1.7nm, 1.7-6.0nm and 10.0-90.0nm. In the beta zeolite preparing process, it uses optimization-condition hydrothermal synthesis method, after synthesis process, firstly proceeding ammonium salt processing procedure to prepare zeolite, then proper-conditioned acid treatment and hydrothermal treatment to prepare final beta zeolite. The prepared beta zeolite having three openings of different aperture, compared with the prior art, it can increase highly the utilization ratio of outer surface of fine grain, decrease diffusion resistance, and improve reaction selectivity. The invented process is simple, the cost is low, and the product repetitiveness is good. The beta zeolite can be used as catalyst for hydrocracking, and so on.