The invention relates to the technical field of a heating system or device, particularly to a parallel-serial type drying and heating system. According to the parallel-serial type drying and heating system, the resistance of a heat exchanger system is reduced, the demands for pressure of a flue gas induced draft fan are reduced, the energy is reasonably distributed, the heating up time for starting of a black furnace of a drying room is reduced, and the energy consumption is reduced. The parallel-serial type drying and heating system comprises a drying room body, a heating combustion furnace, a heat exchanger group, an induced draft fan and a waste heat exchanger, wherein the drying room body comprises a drying room first heating area, a drying room second heating area, a drying room first heat preservation area and a drying room second heat preservation area; the heat exchanger group comprises a first heat exchanger, a second heat exchanger, a third heat exchanger and a fourth heat exchanger; the heating combustion furnace is communicated with the first heat exchanger and the third heat exchanger through a first communicating pipe; the heating combustion furnace is communicated with the second heat exchanger and the fourth heat exchanger through a second communicating pipe; an air inlet end of the first communicating pipe is communicated with an air inlet end of the second communicating pipe; and a communicating position of the air inlet ends is provided with a distribution valve.