The invention relates to the technical field of chemical fiber production, in particular to a production method of glazed fine-denier flat fiber. A glazed polyester melt serves as the raw material; the glazed polyester melt is boosted by a booster pump, then enters a melt cooler to be cooled by the melt cooler and then is conveyed to a spinning manifold, metered by a metering pump, filtered by a spinning assembly in the spinning manifold, extruded, cooled and cured into nascent fiber through a spinning ring air-blowing device, oiled through an oil-passing nozzle, pre-interlaced through an interlacer and controlled to have needed tension through a fiber guide reel integrated on a winder, and then a fiber bundle is guided into the winder to be formed through packaging. According to the production method of the glazed fine-denier flat fiber, the characteristics of flatness, shape specificity and porosity can be organically integrated; by adopting the layout design of line-shaped spinneret orifices, adjusting the length-to-width ratio and independently metering a 20-end production line through a DIO double cavity, the productivity can be doubled, a great cost advantage is achieved, and the glazed fine-denier flat fiber is unique in hand feeling and style and low in production cost.