The solvation structure of 1,4,7,10-tetraazacyclododecane (cyclen) in aqueous solution has been investigated using the Metropolis Monte Carlo scheme. Simulations have been carried out for a system containing 202 rigid particles, including one cyclen molecule, which is fixed at the center of the cube. With a volume of 201 water molecules at 298 K and 1 atm plus additional space occupied by the cyclen molecule, a periodic cubic volume of side length 18.28 Angstrom was yielded. A cyclen-water pair potential has been developed based on nb initio calculations, while the MCY potential was employed to describe water-water interactions. Three hydration layers around the cyclen have been monitored and named the nearest-neighbor, inner hydration, and outer hydration shells. The corresponding numbers of water molecules lying in each shell are 2, 6, and 54, respectively. The two nearest neighbors are bound to the ligand cavity, one above and the other below the ligand plane, pointing one hydrogen atom to the center of the cavity. It was also found that each of them was solvated by three of the six molecules in the inner hydration shell of cyclen. In addition, significant solvent structure around the cyclen molecule has been observed up to 8-9 Angstrom from the molecular center.