This study aims to research the effect of dihydroartemisinin on the proliferation, metastasis and apoptosis in human osteosarcoma cells 143B and the underlying mechanism. This study designed five groups for experiment and control, using dimethylsulfoxide (DMSO), and docosahexaenoic acid (DHA) at concentrations of 15, 25, 35 μmol.L-1 respectively. Experiments including methyl thiazolyl tetrazolium (MTT) assay, clone formation assay, Hoechst 33258 staining assay, luciferase reporter plasmid assay, Western blot and scratch test were carried out. In addition, SPSS 18.0 software from IBM was used for statistical analysis and all the data obtained from the experiments were expressed as mean ± SD, and variance was used to compare the difference between the groups. DHA is proved to be able to inhibit the proliferation and metastasis of osteosarcoma cells, as well as leaving a positive effect on apoptosis in the cytomorphosis. It achieves regulation over the human osteosarcoma cells by keeping the expression of related protein under control.