The invention discloses a catalytic conversion steam stripping device used by a catalytic conversion device in the field of oil refining and petro-chemical industry, solving the problem of low stripping efficiency of the conventional steam stripping device. The steam stripping device adopts a vane-type inner ring steam stripping baffle plate (2) and a vane-type outer ring steam stripping baffle plate (3), and both of which are composed of four, six or eight single vane-type inner ring steam stripping baffle plates and four, six or eight single vane-type outer ring steam stripping baffle plates which are arranged alternately up and down. The projections of the adjacent lateral peripheral area of an upper single vane-type inner ring steam stripping baffle plate and a lower single vane-type inner ring steam stripping baffle plate which are adjacent to each other and the projections of an upper single vane-type outer ring steam stripping baffle plate and a lower single vane-type outer ring steam stripping baffle plate which are adjacent to each other on the horizontal plane are overlapped respectively, and a connecting rib plate (4) is arranged between the lateral peripheral areas and the horizontal planes respectively to form a radial passage (5). The steam stripping device is suitable for the steam stripping of the reclaimable catalyst of entrained oil gas and the regenerated catalyst of the impurity of entrained gas in various processes of catalytic conversion processes.