Objective：To preparate nano—magnetoliposomes containing As2O3，a completely new form of drug for the targeted chemotherapy and thermotherapy to cancer cells．Metheds：The Manganese—zinc ferrite nanoparticles (Mn1．xZn Fe2O4)were prepared by improved wet-chemical reaction．Their characteristics were measured by transmission electron microscope (TEM )and PE thermal analysis system．The radiofrequence—induced hyperthermia was explored in vitro，and their cytotoxicity was measured by the means of MTT．Th e nano-magnetoliposomes were obtained by the combined methods of rotatory film，ultrasonic and churning at high speed．Their characteristics were measured by TEM，computer magic image analysis system and energy dispersive spectrometer(EDS)．The ratio of envelopment of As203 was measured by atom fluorescence spectrometer．Results：Th e average diameter of magnetic particles was about 20-40 nm，round，the cytotoxicity of MnI n Fe2O4 was 0 class．Th e Curie temperature(Tc)of magnetic material varied from 97℃ to 140~C according to different percentages of zinc and manganese in Mn1．xZn Fe204．Th e temperature of magnetic fluid could rise to 35qE-47qE and keep stable in the high frequency alternating electromagnetic field． Th e nano—magneticliposomes contained As2O3 and Mn—Zn ferrite．Th e average diameter of the liposomes was (1 82± 1 25)nm．Th e envelopment ratio of As2O3 was 7 1．1 6％ Conclusion：The nano—particles of Mn1． Zn Fe2O4 are perfect carriers for preparating magneticliposomes； Nano—magnetic—liposomes containing As203 have been successfully preparated．