Abstract: After the discovery of carbon nanoparticles, great attention focused on other nanoparticles and nanocages such as C20 nanocage due to thermal stability, high conductivity, high hardness, gas sensing, hydrogen storage, electronic devices [1], and other adsorption properties[2‒3]. The aim of this study is to investigate the adsorption of hydroxy carbamide (HCA) drug on the surfaces of the pristine and Ni doped C20 nanocage. For this purpose, at the first step we consided different configurations for adsorbing HCA on the surface of nanocage, and then all considered strucures are optimized at the cam-B3LYP / LanL2DZ level of DFT theory by using Gaussian software (09). The quantum parameters, thermodynamic parameters, molecular electrostatic potential, TD-DFT parameters and UV-visible spectrum, density of state (DOS) and MEP graphs are calculated and all calculated results are analyized. The Uv visible results demonstrate that with adsorbing HCA drug and funtionalizing Ni atom the adsorption frequency increased significantly from original state.The HOMO-LUMO and MEP resuls show that the charge density transferred from HCA drug towared nanocage surface and so the the nuclophilic properties of nanocage surface increase. The quantum parameters show that the gap energy of system after adsorbing HCA alters silithly from original state, and so the C20 nanocage is not a good sensor for detecting drug. On the other than the values of thermodynamic parameters such as enthalpy and Gibss free energy for all adsorption models are negative and favorable in thermodynamic approach.This results confirm that the pristine ans Ni doped C20 nanocage can be used as a adsorber for HCA molecule.