The invention discloses a heating control device and method of a drying box for reconstituting tobacco by a papermaking method. The heating control device includes a heat exchanger, a steam valve, a pressure meter, a hot air drying box, a temperature meter, a steam pipeline and a hot air pipeline. A control system receives detection signals of the on-site pressure meter and the temperature meter,reads the operating speed of a production system at the same time, automatically calculates a steam preset pressure value, and outputs the opening degree of the steam valve after through a PID interlocking control circuit composed of the pressure meter and the steam valve. During the production preheating phase, the situation of mechanical damage of heat exchanging equipment caused by water attackis prevented from occurring by controlling the rising slope of the opening degree of the steam valve; and during the production operating phase, the situation that heat exchanging quality is influenced due to phase state changing of the heat exchanger caused by drastic fluctuation of pressure is prevented from occurring by controlling the rising slope and the falling slope of preset parameters ofthe pressure, the smoothness of control is ensured, and the stability of the quality of heated paper sheets is ensured.