The invention discloses a fluid catalytic cracking catalyst containing an aluminum sol binder, and a preparation method thereof. The fluid catalytic cracking catalyst comprises a cracking active component, clay, and a binder; the binder comprises a modified aluminum sol; Al concentration of the modified aluminum sol ranges from 8 to 13wt%, Cl concentration ranges from 4 to 9wt%, Si concentration ranges from 0.1 to 1wt%, Al/Cl weight ratio ranges from 1.2:1 to 2.2:1, and pH value ranges from 2.2 to 5.2. The preparation method of the fluid catalytic cracking catalyst comprises following steps: a slurry is prepared from the cracking active component, clay, the binder, and water, and spray drying is carried out. A preparation method of the modified aluminum sol comprises following steps: metal aluminum, water, and a soluble silicon-containing compound are delivered into a reactor, and a chloride is added for reaction, wherein aluminum silicon feeding ratio is controlled to be 10:1 to 150:1. Compared with conventional aluminum sol binder cracking catalyst, the fluid catalytic cracking catalyst possesses higher cracking activity and coke selectivity.