The invention discloses a preparation method of a solid like phase VOCs degradation high silicon ZSM-5 molecular sieve with controllable crystal grain size. The preparation method comprises followingsteps: 1, a silicon source, an alkali source, a template, ZSM-5 molecular sieve crystal seed, and water are mixed to obtain a gel; 2, the gel obtained in step 1 is introduced into a reaction vessel for hydro-thermal treatment, after reaction, solid liquid separation, washing, drying, and roasting are carried out to obtain a molecular sieve raw powder; and 3, the molecular sieve raw powder is addedinto an ammonium salt solution for ion exchange so as to obtain an ammonium type ZSM-5 molecular sieve, and then roasting is carried out to obtain a HZSM-5 molecular sieve. The preparation method iscapable of increasing product single vessel yield, reducing production cost, reducing mother liquor waste water discharge, and realizing molecular sieve green synthesis; the prepared ZSM-5 high silicon molecular sieve possesses special sphere appearance; and when the ZSM-5 high silicon molecular sieve is adopted in VOCs decomposition, adsorption capacity is high, the hydrophobicity is high, and regeneration is easily realized.