Abstract: Objective To explore the inhibitory effects of Dark Plum Fruit, Lonicera japonica and Caulis Lonicerae Japonicae on Stenotrophomonas maltophilia in vitro. Methods Disc diffusion method was used to screen Stenotrophomonas maltophilia strains that had resistance to 12 kinds of antimicrobial agents(including ciprofloxacin). MH agar dilution method was used to determine the antibacterial effects of Dark Plum Fruit, Lonicera japonica and Caulis Lonicerae Japonicae on strains of Stenotrophomonas maltophilia. The minimum inhibitory concentration(MIC), MIC required to inhibit 50% of tested bacteria(MIC₅₀)and MIC required to inhibit 90% of tested bacteria(MIC ₉₀)of three traditional Chinese medicine were compared. Results A total of 30 strains of Stenotrophomonas maltophilia that had resistance to all 12 antimicrobial agents were screened out. Dark Plum Fruit, Lonicera japonica and Caulis Lonicerae Japonicae all had antibacterial effects, among which Dark Plum Fruit had the best bacteriostatic effect. Conclusion Dark Plum Fruit, Lonicera japonica and Caulis Lonicerae Japonicae have different antibacterial effects against Stenotrophomonas maltophilia. Among them, the Dark Plum Fruit has the strongest antibacterial effect, which reveals that traditional Chinese herbs are worthy of further exploration in application value in the treatment of drug-resistance bacteria.