objective To investigate the Infectious risks and resistant characteristics of Stenotrophomonas maltophilia, and improve the level of clinical prevention and therapy of Stenotrophomonas maltophilia infection. Methods The antimicrobial resis- tance of of 128 strains of Stenotrophomonas maltophilia were determined by standard Kirby-Bauer method according with guidelines of NCCLS(2000). The clinical data about the 128 Stenotrophomonas maltophilia-infection were analyzed. Results Among the nonfermenting Gram-negative bacilli strains were isolated from our hospital, the most predominant pathogens of them was Pseudomonas aeruginosa, followed by Stenotrophomonas maltophilia (23.0%). Most of isolates were extensive-drug resistance. There are only several antibiotics, including sulfanilamide, Ticarcillin/Clavulanic acid, and Cefoperazone/sulbactam, were the active agents against Stenotrophomonas maltophilia with susceptibility rates 50.0% or more. Among the patients with Stenotrophomonas maltophilia infection, approximately to 90.3% of them had basic clinical disease, 97. 0% of them had ever treated with extend-spectrum antibiotics,75.7% of them were treated with invasive examination or therapy. Conclusion Stenotrophomonas maltophilia is becoming to the most predominant pathogens in nosocomial infection, which is easy to infect these immunopromised patients with aged, some chronic diseases, hormone treatment, long periods of antibiotoics therapy and invasive examination or therapy. Multi-drug resistance of Stenotrophomonas maltophilia is a serious problem in clinical therapy. An effective strategy for solving this problem is urgently needed.