Abstract: Taking styrene in coal to olefin MTO process wastewater as the research object，the removal effects of styrene and COD using ultra- violet( UV) and ozone ( O 3 ) oxidation treatment process were studied．The effects of pH，ozone dosage，styrene initial concentration，Al 2 O 3 － Mn and Al 2 O 3 －Ti on ozone oxidation of styrene were carried out．The experimental results showed that under the optimal conditions as pH = 9， ozone dosage 9 mg / min，styrene initial concentration 30 mg / L，reaction time 60 min，the removal rates of styrene and COD oxidation by ozone were 96．5% and 48．1% respectively．With the catalysis of Al 2 O 3 －Mn catalyst，styrene removal rate of ozone catalyzed oxidation for styrene wastewater was better than ozone only，which reached 99．4% after 45 min，the styrene removal rate could be high to 100% after 60 min，mean- while，the COD removal rate was 55．4%．The effects of initial pH，styrene initial concentration，sodium persulfate on UV degradation of styrene and COD were studied．The experimental results showed that under the condition as pH = 3，styrene initial concentration 35 mg / L，the removal rate of the styrene and COD removal rate were 94% and 28% after 120 min respectively treated by UV．With the same conditions，the effect of UV+sodium persulfate was better，as pH = 7 and styrene initial concentration 35 mg / L，the styrene removal rate was 99．4% after 90 min，it could be up to 100% after 120 min，meanwhile，the COD removal rate was 30%．Compared with the other three treatment processes，ozone cat- alyzed oxidation process had some advantages on treatment of styrene from coal chemical wastewater．