The invention discloses a spray gun structure capable of stabilizing the frame spraying distance. The spray gun structure comprises a primary combustion-supporting wind input pipe and a gas input pipe. The primary combustion-supporting wind input pipe is wrapped in the gas input pipe to form a pipe in pipe, so that requirements on gas and flue gas siphoning and premixing can be met, and the premixed combustible gas is enabled to obtain the spraying speed corresponding to the situation that primary combustion-supporting wind input pressure is taken as lower-limit reference pressure to allow the flame sprayed out from a siphon premixed burner to be stable in the spraying distance.