Fe　3O　4　nanoparticles　(NPs)　were　prepared　by　the　co-precipitation　of　Fe　3+　and　Fe　2+　with　ammonium　hydroxide,　and　were　modified　by　four　different　surfactants.　The　modified　Fe　3O　4　NPs　were　characterized　by　Fourier　transform　infrared　spectroscopy,　X-ray　powder　diffraction,　transmission　electron　microscopy　and　vibrating　sample　magnetometer.　Then,　the　modified　Fe　3O　4NPs　were　dispersed　in　ethiodized-oil　by　mechanical　agitation　and　ultrasonic　vibration　to　obtain　stable　Fe　3O　4/ethiodized-oil　magnetic　fluids　(MFs).　The　magnetic　properties　and　rheological　properties　of　the　MFs　were　measured　using　a　Gouy　magnetic　balance　and　a　rotational　rheometer,　respectively.　The　saturation　magnetization　of　the　Fe　3O　4　modified　by　oleic　acid　was　52.1　emu/g.　Furthermore,　the　result　showed　that　the　inductive　heating　effect　of　oleic　acid　stabilized　Fe　3O　4/ethiodized-oil　MF　was　remarkable　and　it　only　took　650　s　for　the　temperature　rising　from　25°C　to　65°C.　The　specific　absorption　rate　of　the　MF　was　50.16　W/(g　of　Fe).　It　had　a　potential　application　in　arterial　embolization　hyperthermia.　Fe　3O　4　nanoparticles　(NPs)　were　prepared　by　the　co-precipitation　of　Fe　3+　and　Fe　2+　with　ammonium　hydroxide,　and　were　modified　by　four　different　surfactants.　The　modified　Fe　3O　4　NPs　were　characterized　by　Fourier　transform　infrared　spectroscopy,　X-ray　powder　diffraction,　transmission　electron　microscopy　and　vibrating　sample　magnetometer.　Copyright　©　2012　SIOC,　CAS,　Shanghai　&　WILEY-VCH　Verlag　GmbH　&　Co.　KGaA,　Weinheim.