The present discloses a catalytic cracking aid for increasing propylene yield, and a preparation method thereof, wherein the catalytic cracking aid comprises 10-75 wt% of a phosphorus-containing and loaded-metal-containing MFI structure molecular sieve (calculated as the dry base weight), 3-40 wt% of a phosphorus-aluminum inorganic binder (calculated as the dry base weight), 1-30 wt% of other inorganic binder (calculated as the oxide), 0-60 wt% of second clay (calculated as the dry base weight), and 0.5-15 wt% of at least a metal additive (calculated as the oxide) selected from a group VIII metal, manganese, zinc and gallium by using the dry base weight of the catalytic cracking aid as the reference. According to the present invention, the catalytic cracking aid can effectively improve propylene yield and propylene selectivity in the catalytic cracking.