a catalytic conversion process can convert inferior feedstock to high quality fuel oil and propylene . a inferior feedstock is introduced into first and second reactor zone , wherein the feedstock carry out first step and second step reactions by contacting with catalytic conversion catalyst . product vapors separate from spent catalyst by gas - solid separation . the spent catalyst is stripped , regenerated by burning off coke and then returns to reactor . the product vapors are introduced into separation system to obtain propylene , gasoline , diesel , fluid catalytic cracking gas oil and other products . the fgo is introduced into hydrotreating unit and / or extraction unit to obtain hydrotreated fgo and / or extracted fgo . said hyrotreated fgo and / or extracted fgo return to the first reactor zone and / or another catalytic cracking unit to obtain propylene and gasoline . the extracted oil of said fgo is rich in double ring aromatics which are good chemical materials . the raffinate of said fgo is rich in chain alkane and cycloalkane which are suitable for catalytic cracking . more particularly , the invention relates to a process to utilize petroleum oil resources efficiently for decreasing the yield of dry gas and coke significantly .