Abstract: The application of catalytic cracking additive FLOS-III for more propylene and isobutene in a 1.05 Mt/a MIP-CGP FCC unit of Baling Refining and Chemical Company was described. The first application shows that when the inventory ratio of the additive reaches 6%, the yield of LPG, propylene and isobutene increases by 2.68 percentage points, 1.01 percentage points, and 0.54 percentage point, respectively, with improved product distribution. The yield of the poor quality and low added value LCO decreases by 2.09 percentage points, the coke yield decreases by 0.25 percentage point, while the total liquid yield increases by 0.17 percentage point. The yield of gasoline and its RON is similar to the blank test. It is concluded that the use of additive FLOS-Ⅲ is helpful to produce more propylene and isobutene with significant economic benefits.