Abstract: Combined with the experimental analyses and numerical simulation,the factors influencing the scarring were analyzed based on the current situation of scarring in an oxidation reactor for chloride process titanium dioxide.The results show that the high temperature gas tends to adhere on the cold wall of gap before TiCl₄ feeding,causing scabbing of the oxidation reactor.The ways to prevent scabbing before feeding gap include the enhancement of wall temperature of the reactor and decrease of the gas liquefaction.The fluidization state of mixed fluids is affected by the structure of the oxidation reactor.Increasing the width of feeding gap and optimizing the momentum ratio of TiCl₄ and O₂ can effectively prevent and decrease the scabbing after the feeding gap.The scabbing reduces the inner diameter of the reactor and increases the system pressure dramatically,which leads to shutdown of the furnace and shortens the operation cycle.