Abstract: The monoclonal antibody JH W (McAbJHⅢ ) against human hepatocellular car-cinoma was radiolabeled with ¹³¹I by Ch-T method. Its distribution and radioimmunoimaging in the nude mice bearing human hepatoma BEL-7402 were studied. Between 24-120 h after intraperitoneal administration, the image of the concentrating radioactivity in tumor was obtained by the 丫 camera and it was the clearest during 72—96 h； whereas the injection 6f ¹³¹I-mIgG into the nude mice resulted in an equal distribution in the whole body without any selectivity. At 72 h after the injection of ¹³¹I-McAb JHW, the radioactivity ratioes of tumor/normal tissue (T/NT) for 13 kinds of organ/tissue were all over 5, and the localization index of tumor was 7.07. These results showed that McAbJHⅢ may be used in the localization and targeting treatment of human hepatocellular carcinoma.