Abstract: The hydrodynamic characters,disturbance of bubble motion to bed and relationship between bubble size and distributed plate position under the initial fluidization velocity in fluidized chlorination of high-titanium slag in Yunnan was studied based on the Euler Two-fluid Model and Critical Fluidization Velocity Empirical Formula for fluidized chlorination,combining with the physical parameters of Yunnan high-titanium slag.The results show that the Grace Correlation can precisely predict the bubble behaviors in fluidized chlorination of the high-titanium slag with narrow size distribution of B-type particles,and the appearance of emulsion phase and bubbles predicted by Wen-Yu Correlation under initial fluidizing velocity is postponed.The bubbles are formed at the distributed plate positions through three stages of rise,consolidation and burst under full fluidizing velocity.The solid-vector diagram of the high titanium slag indicates that the whole bed is demarcated by the bubbles and the bubble rising process affects the fluidization of upper and lower particles which results in unevenness of the entire bed.