The malignant neoplasm is a worldwide disease and has been ranked in the leading causes of the death for Taiwan people in 2006. There are many different methods of cancer treatments, such as surgery, chemotherapy, radiation therapy, and direct heat hyperthermia, but the effectiveness of these therapies is limited by the complications of cancer. Magnetic induction hyperthermia can apply heat to cancers at the deep region in a living body and overcomes some disadvantages of conventional cancer treatments. Ammonium ferric citrate exhibits biological activities and are used as a contrast agent for magnetic resonance imaging due to its magnetic property. Folic acid is a high affinity ligand of the folate receptor which is absent in most normal tissues and overexpressed on various types of tumors. Therefore, folic acid conjugated ammonium ferric citrate administered intravenously is supposed to be taken by cells via receptor –mediated endocytosis. In this study, folic acid conjugated ammonium ferric citrate was prepared by carbodiimides cross-link agent. Targeting AFC was characterized by FTIR, NMR, VSM, and AA analysis. Cytotoxicity and proliferation of materials to cells were evaluated by crystal violet, LDH, and WST-1 biological assay kits.