Unsymmetrical dimethylhydrazine (UDMH) is a kind of cheap propellant for rocket luanching. But it is harmful to environment and human body. At present, the majority of UDMH eliminating agents are unsafe and inconvenient for use because of strong oxidizing property. The eliminating effects of vitamin B6, vitamin C and glacial acetic acid on UDMH are studied. 1mg vitamin B6 , 1mg vitamin C and 1mg glacial acetic acid is added into 10.00ml UDMH solution (1μg/ml) respectively, UDMH content is determined respectively in 30 minutes and 60 minutes through amino sodium ferrocyanide (TPF) spectrophotometry method at wavelength 500nm. The results show that vitamin B6 can eliminate 88% UDMH in 30 minutes. Vitamin C or acetic acid has no significant removal effect on UDMH. The chemical mechanism of vitamin B6 eliminating UDMH is that pyridoxal and pyridoxal 5 – phosphate monohydrate (PLP) can react with UDMH and generate hydrazone and water.