A spray structure of a water spray gun is formed on a surface cover of the water spray gun. The surface cover is formed with a plurality of spray orifices. The inner side of the surface cover is formed with annular flanges each corresponding to the edge of each spray orifice. Each flange is formed with a tangential opening. The surface cover of the present invention is formed with the tangential opening instead of the inclined opening of the water distribution member of the prior art. When the water flows to the tangential opening and then enters the flange to be rotated and sprayed out through the spray orifices. The tangential opening of the present invention is flat and smooth and won't be blocked. The water spray gun won't be damaged easily and has a long service life. The cost is reduced.
