The invention provides a spray drying gun head assembly. The spray drying gun head assembly includes a fixed nozzle head, an adjusting ring, an adjusting cover and a nozzle; the nozzle comprises a cylinder body and a convex stretching ring, the convex stretching ring is provided with a plurality of flow channels, the side portion of the fixed nozzle head is provided with a liquid inlet and a gas inlet, a first cavity and a second cavity are formed inside the fixed nozzle head and communicated. the liquid inlet is communicated with the first cavity, the gas inlet is communicated with the second cavity, and a necking portion and a spray pipe are formed at the tail end of the cylinder body. The inner wall of the cylinder body is fixedly provided with two anti-push retainer rings and a bearing which is limited through the two anti-push retainer rings; a flow stabilization ring is arranged on the bearing in a clamped mode, used for limiting the turbulent flow of liquid and composed of a plurality of rotary vanes which protrude inwards in the radial direction. By the arrangement of flow stabilization ring on the inner wall of the cylinder body, when the liquid passes through the inside of the cylinder body at a high speed, the turbulent flow of the liquid can be limited, so that the liquid can passes through the cylinder body steadily at the high speed, and the atomization effect of the spray drying gun head assembly is improved.