The invention relates to the technical field of molecular sieve preparation, and discloses a preparation method of a hierarchically porous zeolite molecular sieve. The specific surface area of a hierarchically porous EU-1 molecular sieve is improved. The method comprises the steps that a template agent part of EU-1 molecular sieve original powder is firstly removed through temperature controlling,then the processed EU-1 molecular sieve is placed in an acid solution to be reacted for 12-48 hours at the temperature of 100-150 DEG C, and finally the EU-1 molecular sieve is placed in an alkali solution where CTAB is dissolved to be reacted for 2-48 hours at the temperature of 80-180 DEG C to obtain the hierarchically porous EU-1 molecular sieve after sintering is conducted. The method has theadvantages that the hierarchically porous molecular sieve is prepared by the joint processing of desilicification and CTAB auxiliary secondary crystallization bonding through sintering temperature controlling and acid treatment, the method is simple, the outer specific surface area of the formed hierarchically porous EU-1 molecular sieve is increased, the dispersing performance of the molecular sieve is improved, and the catalytic activity is further improved.