The invention relates to a method for preparing beta zeolite by taking kaolin microsphere as a raw material. The method comprises the following steps of: taking the roasted kaolin microsphere as a main silicon aluminium source; adding a part of coarse pore silica gel as a supplement silicon source; adding to an aqueous solution with a sodium source and a tetraethylammonium cation source to mix uniformly; and crystallizing at 120-180 DEG C for 24-60 h. The reaction system comprises the following compositions according to mol ratio: SiO2/Al2O3 is 5-100; and Na2O/SiO2 is 0.029-0.31. According tothe method disclosed by the invention, on the premise of not damaging the external form of the kaolin microsphere, the roasted kaolin microsphere is adopted as the silicon aluminium source to performin-situ crystallization so that the beta zeolite is synthesized; the reaction is carried out under an ultra-thick system; the crystallization time is short; the product concentration is high; and theobtained beta zeolite can be directly used for FCC (Fluid Catalytic Cracking) reaction by slight modifying.