This study was performed to convert NOx in atmosphere by photochemical reaction utilizing the eco-friendly solar energy. The mortar specimen coated with photocatalyst was fabricated and the photochemical conversion efficiency of NOx was analyzed. The photocatalyst coated concrete was fabricated by first adding TiO2 photocatalyst on the bottom of mold first and next adding cement mortar and, then, curing the concrete mortar. The grease was sprayed on the bottom of mold in advance so that the concrete can be demolded easily after curing. The conversion efficiencies of NOx by photochemical reactions were investigated systematically by changing the process variable conditions of amount of TiO2 coating, UV-A light intensity, total gas flow rate, relative humidity and initial NOx concentration. It was confirmed that the photocatalyst coated concrete fabricated in this study could convert NOx successfully for various process conditions in atmosphere. In future, we believe this research result can be utilized as basic data to design the infrastructure of building, tunnel and road for controlling efficiently the air pollutants such as NOx, SOx, and VOCs.