The in-situ annealing of NdBa2Cu3O7-delta (NBCO) thin films was conducted so as to find means for improving chin film quality. NBCO thin films were prepared on a MgO (100) substrate by single target dc-magnetron sputtering. After deposition, while cooling to room temperature, films were annealed at 600-350 degrees C for 0.5-80 h under 300 Torr O-2 gas atmosphere in the deposition chamber. Superconducting properties as well as features such as resistivity in the normal state and surface roughness were improved by optimizing annealing parameters. Highly c-axis oriented thin films having zero resistance temperature (T-c = 94.3 K) were obtained by in situ annealing treatment. Thin films with critical current density (J(c)) of 1x10(6) A/cm at 77 K, and mean surface roughness of 5.5 nm were obtained under optimal annealing conditions.