The invention belongs to the field of biomass pyrolysis and in particular relates to a heat accumulation type biomass pyrolysis and carbonization reaction system and method. The system comprises a hopper, a chain plate type drying machine, a heat accumulation type pyrolysis reactor, a slag cooling machine, a condensation air blowing system and a purification system, wherein the chain plate type drying machine is connected with the hopper; the hopper is connected with a feeding hole; the heat accumulation type pyrolysis reactor comprises a pyrolysis room, a double heat accumulation type radiation tube system, a feeding hole, a discharging hole and a pyrolysis gas outlet system; the condensation air blowing system is arranged between the heat accumulation type pyrolysis reactor and the purification system; an inlet of the condensation air blowing system is connected with a pyrolysis gas leading-out hole and an outlet of the condensation air blowing system is connected with the purification system; the purification system is connected with the condensation air blowing system and a fuel gas burner. According to the reaction system provided by the invention, the temperature is reasonably controlled and the design of radiation tubes can be simplified so that the investment cost is reduced; a continuous carbonization process is realized by combining comprehensive utilization of biomass products and layered heat accumulation type control.