A built-in air-assisted spray head comprises an external shell and an internal spray head body. An air inlet in the rear end of the shell is connected with a centrifugal fan, and a liquid inlet of the spray head body is connected with a hydraulic pump. The front portion of the shell comprises a first cylindrical inner cavity pipe segment, and the first inner cavity pipe segment and an air outlet of the shell are connected through a first tapered inner cavity pipe segment which gradually shrinks. The front portion of the spray head body is provided with a spray head cap, and an annular gas channel is formed between the spray head cap and the inner cavity wall of the shell. The spray head cap is composed of a tapered cap body part on the front portion and a cylindrical cap body part on the rear portion. The outer wall of the tapered cap body part and the inner wall of the first tapered inner cavity pipe segment are consistent in inclination direction, the external diameter T of the cylindrical cap body part is larger than the diameter L at the narrowest position of the air outlet, and the difference is 2 mm or above. According to the built-in air-assisted spray head, the air speed on the periphery of the air outlet can be larger, the air speed on the inner circumference of the air outlet is smaller, a certain internal included angle is formed by the wind directions of the air outlet, wrapping and transporting of the wind field for mist drops can be enhanced, and accordingly the targeting of the spray head is improved.