To investigate the decorporation and radiation protection effects of WSC-DTPA nanoparticles on internal uranium exposure, the methods as followed were used. After SD rats were exposed to 0.5 mgU•kg-1 uranyl nitrate by intraperitoneal injection, 92.7% WSC-DTPA nanoparticles, 1.59% WSC-DTPA nanoparticles, WSC nanoparticles and DTPA-CaNa3 were administered at 60 mg•kg-1 dose through tail vein immediately. The contents of uranium in urine and feces at 1st, 2nd and 3rd day were measured by ICP, as well as those in liver, spleen, kidney and bone after 3 days. Exposed to 2.0 mgU•kg-1 uranyl nitrate for 5 days, the contents of uranium in liver, spleen, kidney and bone were determined, and the functions of liver, spleen, kidney and bone were evaluated with pathological section and bone marrow cell smear. As a result, we found that 92.7% WSC-DTPA nanoparticles, 1.59% WSC-DTPA nanoparticles and DTPA-CaNa3 have good decorporation effect, while 1.59% WSC-DTPA nanoparticles is significantly superior to DTPA-CaNa3 (p<0.05). At the group of 0.5 mgU•kg-1, the uranium contents in liver, spleen, kidney and bone in treated groups are significantly lower than the control group. It is obvious that 92.7% WSC-DTPA nanoparticles have protective effects on liver and kidney by tissue pathological sections in the dose of 2.0 mgU•kg-1. Therefore, it is suggested that 92.7% WSC-DTPA nanoparticles could have both good decorporation and radiation protective effects against the internal uranium exposure.Cited