Abstract: Objective: To explore the distribution of ¹²⁵I-EGF-targeting nano-carrier BSA in nude mice bearing SK-BR3 hu-man breast cancer. Methods: We used ultrasound emulsification-chemical cross-linking to prepare bovine serum albumin nanoparticles. Through a carboxymethyl reaction, the active amine group on the surface of albumin nanoparticles was cou-pled with EGF, forming EGF-conjugated albumin nanoparticles.Nude mice were used to establish the human breast cancer model and were randomly divided into three experimental groups:¹²⁵I-BSA non-nano-carrier group (¹²⁵I directly linked to BSA),¹²⁵I-EGF-BSA targeting nano-carrier group, and 125 I-BSA nano-carrier group. The radioactive distribution of the particles in different tissues was detected and calculated. Results: The tumor/blood ratio and tumor/muscle ratio in the 125 I-EGF-BSA targeting nano-carrier group were higher than those in the other two groups (P<0.05). The distribution of 125 I-EGF-BSA targeting nano-carrier in the liver, spleen, lungs and other organs was significantly lower than that in the other two groups (P<0.05). Conclusion: ¹²⁵I-EGF-BSA targeting nano-carrier has obvious tumor-targeting effects on hu-man breast cancer SK-BR3 in nude mice and is distributed to the liver, spleen, lungs and other organs less effectively.