The invention provides a method and device for producing reduced iron through synthetic gas prepared from high-nitrogen content retort gas. The method comprises the steps of purifying and desulfurizing the high-nitrogen content retort gas until the sulfur content thereof is smaller than or equal to 10ppm; heating the desulfurized retort gas to the temperature of 300 DEG C to 650 DEG C as to-be-transformed gas, or adding part of superheated steam into the retort gas according to the constitution of the retort gas as the to-be-transformed gas; leading the to-be-transformed gas into a reforming furnace which contains a catalyst to transform the to-be-transformed gas on the catalyst so as to obtain the synthetic gas containing H2, CO and N2; taking the synthetic gas formed after the transformation as completely or partially-reduced gas, and directly sending the synthetic gas into a gas-based shaft furnace to reduce iron oxide so as to produce the reduced iron. After the N2, CO2 and sulfide are removed, the tail gas at the furnace top can be returned to the shaft furnace to be recycled as reducing gas. The method and the device disclosed by the invention are used for improving the use values and efficiency of the retort gas and realizing an effect and an aim of producing the reduced iron by taking the natural gas as a raw material.