The invention provides a single inclined tube type outlet multi-tube gaseous state fuel mixing device which comprises a shell. A center fuel channel, a peripheral fuel channel and an annular air channel are coaxially formed in the shell in the radial direction; the center fuel channel comprises a center fuel conveying pipe and a center fuel spraying nozzle connected to the tail end of the center fuel conveying pipe; the peripheral fuel channel comprises a peripheral fuel conveying pipe and a peripheral fuel spraying nozzle connected with the peripheral fuel conveying pipe; the annular air channel comprises a peripheral air channel and a center air channel, the peripheral air channel comprises a plurality of pipes evenly distributed in the peripheral direction, inclined tubes are connected to outlets of all pipes, and a certain inclined angle is formed between the axis direction of the inclined tubes and the axis direction of the pipes. According to single inclined tube type outlet multi-tube gaseous state fuel mixing device, the multi-tube pre-mixing mode of the peripheral channels and the tail end inclined tubes are applied, oil-gas mixing is even, and pollution emission is reduced.