Abstract: Due to high content of TiO₂ with excellent photocatalytic degradation and wide source of availability at cheap cost,the BF titaniferous slag has drawn broad attention and interests focused on its efficient and rational utilization.The slag rich in TiO₂ was treated by process of acid leaching with hydrochloric acid（analytical reagent） for different length of time at room temperature,and then various tests such as specific surface area（SSA）,scanning electron microscope（SEM）,energy dispersive spectrum（EDS） and formaldehyde absorbing tests for the resulting absorbent were performed.According to the test results,the absorbent samples having a porous structure on the surface exhibited a good ability to absorb formaldehyde with their specific surface area increasing from 4.56 m²/g up to 105.35 m²/g;Ti content in the absorbent increased from 15.33 % up to 31.39 %（39.6% as TiO₂ content）,which implies that TiO₂ in titaniferous slag can be enriched by acid leaching.In our research,the best result turned out to be the sample dealt with HCl for 5 hours with TiO₂ content of 34.7 % and SSA of 105.35 m²/g.This sample is able to absorb 0.36 mg/g of HCHO,which is three times of activated carbon（0.12 mg/g） merchandised in the market.