The invention discloses a vertical furnace convenient for stably heating. The vertical furnace comprises a vertical heating furnace discharge port, a lower temperature sensor, an upper temperature sensor, a feeding port, a discharge port, heating devices with automatic control systems, manual valves, an electromagnetic valve, a flow meter, an electric heating belt with an automatic control systemand a hot blast stove; the discharging port of the vertical heating furnace is positioned at the bottom part of the columnar heating furnace, the lower temperature sensor is arranged at the position,close to the lower part, of the side surface of the columnar heating furnace, the upper temperature sensor is arranged at the position, close to the upper part, of the side surface of the columnar heating furnace, the heating devices with the self-control systems are wound on the side surface of the columnar heating furnace, and heat preservation layers are arranged outside the heating devices; and cross-arranged pipelines are arranged inside the hot blast stove, and the electric heating belt with the automatic control system is arranged on the side surface of the hot blast stove. The verticalfurnace has the advantages that the whole is designed into a closed container, the bottom part and the top part of the vertical furnace are controlled to be opened by the valves, normal-pressure or pressure-maintaining heating operation can be realized, the ertical furnace is relatively flexible, temperature control is accurate, and heating is stable.