On the basis of the unsymmetric dimethydrazine (UDMH)-degrading bacteria preserved in laboratory, the compound flora FYD was build with a view to use in the emergency situations when UDMH leaked into water. The optimal conditions for degradation of UDMH determined by effect factors experiments are as following: temperature 35 ℃, the medium pH 7.2, inoculation 2%, the initial UDMH concentration 50 mg·L^-1. Under this condition, the highest UDMH degradation rate, is 99.10%, and UDMH residual concentration is less than 0.5 mg·L^-1 in 72 h, and all the indicators of water meet the requirements of GB1473-93 emission standards.