Abstract: The effect of HH07A on the growth of tumor cells in vitro was jnvestigated usingthe techniques of cell growth curve determination and soft-agar colony-forming assay.The resultshowed that HH07A inhibited the growth of L1210 cells and HL-60 cells at a concentration of 1.5μg· ml^-1 and 4.0μg· ml^-1,respectively.Among the cells tested,L1210 cells were shown to be themost sensitive,followed by KB cells and HL-60 cells(with IC₅₀ of 2.29,4.13 and 4.36μg· ml^-1,respectively). Normal mouse granulocyte-macrophage progenitor cells(GM-CFC)were less sensitiveto the drug(with IC50 of 11.15μg·ml-1)as compared with the tumor cells.As they were exposed toHH07A 3.5μg·ml^-1 for 5 days,HL-60 cells did not show NBT reductive ability. Intraperitonealinjection of HH07A exerted inhibitory effect on the ascitic tumors of L1210 and S180 in mice.oral orip administration of HH07A also showed some effect on S180 solid tumors in miee.