Oxidation system of H₂O₂-UV-O₃ to oxidize the unsymmetrical dimethylhydrazine(UDMH) waste water was established. Using the removal efficiencies of UDMH and chemical oxygen demand(COD) as the detection indexes, the main factors affecting the reaction and the optimal technological conditions were determined through an orthogonal experiment. The degradation efficiencies of four systems: O₃ system, UV-O₃ system, UV-H₂O₂ system and H₂O₂-UV-O₃ system were compared. The variation law of intermediate products was explored preliminarily. Results show that: the removal efficiencies of UDMH and COD in UDMH waste water(mass fraction, 1%) can reach up to 99.99% and 99.30%, respectively in the following conditions: air blows in hydrogen peroxide at pH 9.0 for 24 h, ozone addition rate is 19.6 mg·L^-1·min^-1, molar ratio of hydrogen peroxide to UDMH is 5:1, the ultraviolet type is VUV+UV-C, the reaction time is 1.5 h.