Abstract: The present invention relates to a catalytic conversion apparatus, characterized in that said apparatus comprises at least one feed oil cracking riser reactor, a dense bed reactor, a disengager, and a stripper, wherein said stripper locates below said dense bed reactor and communicates directly with the lower part of the dense bed reactor or through a fluid-communicating channel, the outlet of at least one of said riser reactor(s) communicates with the lower part of said dense bed reactor or any part of said fluid-communicating channel, the outlet of said dense bed reactor communicates with the inlet of a gas-solid separating apparatus located in said disengager through said disengager and/or through an optional transporting channel, the catalyst outlet of said disengager communicates with at least one position selected from the upper part of said stripper, any part of said fluid-communicating channel, and the lower part of said dense bed reactor, through at least one catalyst transporting channel.