Considering the complex elemental and phase compositions, it is a challenge to realize the high value utilization of solid residues in the preparation unit of fluid catalytic cracking catalysts (i.e., FCCR). The current research proposes a disposal approach of FCCR by a direct transformation from FCCR to mordenite molecular sieves. Species evaluation of FCCR in alkaline fusion activation is investigated. Ageing temperature/ duration, crystalline temperature/ duration, amount of water and silica sol are systematically optimized. Obtained mordenite molecular sieves are pure and highly crystallized. When employed as catalysts for the isomerization of α-pinene, as-synthesized mordenite molecular sieves have a comparable performance with commercial ones due to the low diffusion resistance of hierarchical pore structure. These researches are important as a reference for the utilization of FCCR in the field of zeolitic synthesis.