The invention relates to a gaseous hydrocarbon reformer nozzle. The gaseous hydrocarbon reformer nozzle mainly comprises a central spray pipe, an inner annular spray pipe and an outer annular spray pipe, which are coaxially arranged, as well as a gasification agent passage, an auxiliary gasification agent passage, a fuel passage and a cooling system. The gaseous hydrocarbon reformer nozzle is applied to a gaseous hydrocarbon reformer, and the gasification agent corresponds to the fuel, so that the temperature of the flame formed by the nozzle is low and is uniformly distributed, the flameless conversion in the reformer can be realized, materials in the reformer are uniformly mixed, and the conversion rate of methane is increased. The nozzle has the advantages of simple structure, long service life, high methane conversion rate, wide application range and the like, and has wide application prospects.