Abstract: This work is to evaluate the toxicity of the synthetic peptides on mononuclear macrophage THP-1 of human leukemia and the intracellular bacteriostatic effect on Mycobacterium tuberculosis H37Rv. The minimum inhibition concentration（MIC）of the synthetic polypeptide on H37Rv was determined through the different drug concentrations of poly-peptides. Then，the toxic effects of peptide-2 on THP-1 cells were detected using flow cytometry method and MTT method. The colony-forming unit（CFU）method was used for detecting intracellular bacteriostatic effect of peptide-2 on H37Rv. Results were as below：All 4 screened peptides had bacteriostatic effect，the MIC of peptide-2 was 200 mg/mL. When the peptides-2 interacted with THP-1 cells，the cytotoxicity emerged at the concentration of 1200 mg/mL，meaning that there was no significant difference from INH’s cytotoxicity. For intracellular H37Rv，the anti-tuberculosis effects of peptide-2 presented time- and dose- dependent effect，the H37Rv colony count was obviously decreased with the increase of the time and dose. In conclusion，not only has the peptide-2 small toxicity to the macrophage THP-1，but also solid intracellular anti-M. tuberculosis effect，and it can be a new and potential anti-tuberculosis drug.

Key words: synthetic peptide, Mycobacterium tuberculosis, macrophage, intracellular inhibitory