Abstract: Objective To investigate the anti-tumor effect and its mechanism of Musca domestica larvae of three age by solid phase extraction.Methods The in vitro anticancer effect of the hemolymph extraction from Musca domestica with 40% acetonitrile(ACN)in aqueous solution by solid phase extraction was studied with 3(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-terazolium bromide(MTT) assay; tumor inhibition effect of the extraction on S180 sarcoma-bearing mice was observed.Total antioxygen capability(T-AOC),superoxide dismutase(SOD),and malondialdehyde(MDA) were detected.Results At 25 μg/mL concentration,the inhibitory rate of the S180-cells proliferation was increased to 79%.The inhibitory rate of the cell proliferation was different compared with that of the control group.For low,moderate,and high dosage treatment group,the tumor inhibition rates for mice bearing S180 were 32.13%,36.23%,and 45.23%.The activity of T-AOC and SOD was higher and the content of MDA was lower in the extraction treatment group than those in the control group,with significant differences compared with those of the control group(P<0.05,P<0.01).Conclusion The hemolymph extraction from Musca domestica with 40% ACN solid phase extraction has anti-tumor effect on S180 sacoma cells both in vivo and in vitro and the effect is probably related to antioxidation of the extraction.