The invention discloses a non-equilibrium state photocatalytic reaction device and application thereof. A first branch pipe (21) is arranged on the upper portion of a reactor (1) of the reaction device, a second branch pipe (22) is arranged on the lower portion of the reactor (1), multiple air holes (10) are formed in the first branch pipe (21), multiple sprayers (3) are arranged on the second branch pipe (22), and the first branch pipe (21) is connected with an air compressor (5) through an air inflow pipe (11). An inlet of the second branch pipe (22) is connected with a water inflow pipe (4), the water inflow pipe (4) is connected with a water pump (6), and a water outflow pipe (7) is arranged at the bottom of the reactor (1). An ultraviolet lamp tube and a catalyst are arranged in the reactor (1). The photocatalytic reaction device is simple in structure, a gas phase and a liquid phase are in countercurrent contact in the vertical direction in a high-speed flowing state, liquid fully makes contact with a light source and a catalyst coating, the contact area is increased, the reaction efficiency is improved, and the non-equilibrium state photocatalytic reaction device is suitable for various photocatalytic reactions and especially suitable for industrial treatment of high ammonia-nitrogen wastewater.