The invention discloses a microbacterium 18 for degrading unsymmetrical dimethylhydrazine, and provides a method for degrading unsymmetrical dimethylhydrazine with the microbacterium 18. The method comprises the steps of: inoculating a microbacterium 18 strain in a slant culture medium composed of tryptone, malt extract, bacto peptone and agar for culturing so as to obtain a slant culture; inoculating the slant culture in a container loaded with a seed culture medium composed of tryptone, malt extract, and bacto peptone for culturing so as to obtain a seed solution; inoculating the seed solution in a container loaded with a substrate solution composed of cane sugar, NaCl, K2HPO4, KH2PO4, MgSO4, CaCl2, FeSO4, H3BO3, ZnSO4 and unsymmetrical dimethylhydrazine for culturing, and conducting degradation at a temperature of 28-37DEG C for 72h. With the microbacterium 18 and the method that are provided in the invention, the degradation rate of unsymmetrical dimethylhydrazine can reach 88.06%.