Hierarchical mesoporous zeolite Beta microspheres (Beta-MPs) from assembly of nanocrystals were successfully one-step-synthesized through a simple polymer agent. The Beta-MPs sample was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), nitrogen adsorption isotherms, and thermogravimetric analysis. The characteristics of the samples are comparable with conventional Beta zeolite. The Beta-MPs with a hierarchical mesoporous structure and a uniform size could be easily separated with filtration. This procedure successfully avoided the high-speed centrifugation of the nano-zeolites during the traditional method. As catalysts, the Beta-MPs showed higher catalytic activity and selectivity than conventional Beta in alkylation of benzene with isopropanol to cumene.