Numerical model that considered the shrinking core model and elutriation and degradation of particles was developed to predict selective chlorination of ilmenite and carbo-chlorination of TiO2 in a two stage fluidized bed chlorination furnace. It is possible to analyze the fluidized bed chlorination reaction to be able to reflect particle distribution for mass balances and the chlorination reaction. The numerical model showed an accuracy with error less than 6% compared with fluidized bed experiments. The chlorination degree with particle size change was greater with a smaller particle size, and there was a 100 min difference to obtain a chlorination degree of 1 between 75 μm and 275 μm. This was not shown to such a great extent with variation of temperature (800 ~ 1000 ℃), and there was only a 10 min difference to obtain a chlorination degree of 0.9. In the first selective chlorination process, the mass reduction rate approached to the theoretical value of 0.4735 after 180 min, and chlorination changed the Fe component into FeCl2 or FeCl3 and showed nearly 1. In the second carbo-chlorination process, the chlorination degree of TiO2 approached 0.98 and the mass fraction reached 0.02 with conversion into TiCl4. In the first selective chlorination process, 98% of TiO2 was produced at 180 min, and this was changed into 99% of TiCl4 after an additional 90 min. Also the mass reduction rate of TiO2 was reduced to 99% in the second continuous carbo-chlorination process.