Abstract: Absorption distribution and excretion of ⁶³Ni-NiCl₂ administered orally to rats were studied by using liquid scintillation counting method. It was observed that the concentration-time curves in blood fitted the two compartment model of pharmacokinetics, K_a=6.18 h^-1, T_1/2α=0.79 h, T_1/2β=40.68 h, CL=0.42 mL·kg^-1·h^-1, T_max=0.53 h, C_max=24 987.75 min^-1·mL^-1, and V_d=0.016 L·kg^-1. After rats were treated by ⁶³Ni-NiCl₂ for 15 days, in 22 tissues tested, the contents of ⁶³Ni-NiCl₂ in hair, hypothalamus, hypophysis, pancreas, small and large intestines were higher, and the residua of ⁶³Ni-NiCl₂ was not discovered in liver, kidney and heart. Radioactivity eliminated was 83.27% by urine and feces, 54.86% by urine, 28.41% by feces.