This study characterized the effects of artesunate on thyroid cancer and partially identified its related molecular mechanism. We determined the effect of artesunate on the proliferation of thyroid cancer cells using the MTT assay, cell colony formation experiments, and western blotting, and used flow cytometry to detect the apoptosis of cancer cells. Using a wound-healing assay, Transwell chamber experiments, and western blotting, we determined the effect of artesunate on cancer cell migration. By co-cultivating artesunate with the PI3K agonist, 740Y-P, we also partially identified the molecular mechanism. Artesunate significantly inhibited the growth, proliferation, migration, and invasion of thyroid cancer cells, and promoted the apoptosis of cancer cells. Using co-cultivation with a PI3K agonist, we found that the inhibitory effect of artesunate on cancer cells was mainly due to suppressing the PI3K/AKT/FKHR signaling pathway. By inhibiting the PI3K/AKT/FKHR signaling pathway, artesunate induced apoptosis of thyroid cancer cells and inhibited their proliferation and migration.