Abstract: The investigation of a MIP-LTG process for enhancing high octane gasoline production by cracking heavy diesel fraction was conducted in a continuous catalytic cracking unit. The test results show that a high yield of good quality gasoline can be obtained at high conversion and propylene yield in appropriate reaction temperature range. By increasing catalyst to oil ratio, the conversion, liquefied gas yield, gasoline yield and octane number are all increased, while more dry gas and coke is observed as well. The properties of feed have a critical influence on the product distribution and properties. The higher aromatic content, in particular, the higher monocyclic aromatic content in the feed, the higher content of aromatics in the gasoline product, and the higher gasoline octane.