Objective To study the bacteriostasis of Chenopodium ambrosioides L. against HP metronidazole resistant and susceptible strains in vitro. Methods The minimal inhibitory concentrations （MIC） of Chenopodium ambrosioides L. against HP were selected,agar dilution method used to observe the effect of the drug on the growth of HP under different drug concentrations and different action times,with HP metronidazole resistant strain （26695-16R,26695-8 R16S,26695-2 R8S） and susceptible strains （NCTC 11637,26695）setting as the experimental strains. Results Chenopodium ambrosioides L. was active against HP metronidazole resistant and susceptible strains under different action times （MIC value 4 ～ 256 μg/m L）,and the differences of MIC values decreased with the prolongation of drug action time. Conclusion Chenopodium ambrosioides L. had bacteriostasis to HP metronidazole resistant and susceptible strains. The antibacterial effect was positively related with the drug concentrations and the effect tended to be stable after 72 h.