The invention discloses a protection ventilation device and a method, and belongs to the technical field of protection engineering. The protection ventilation device comprises a display control unit and a ventilation cabinet unit, the display control unit comprises a control interface circuit, a rectifier and a direct-current power supply distributor, a detector interface circuit, an AD conversioncircuit, an FPGA processor, an ARM processor and a touch display screen; the ventilation cabinet unit comprises a cabinet body, a filter, a first cleaning valve, a second cleaning valve, a three-proofing machine, a three-way box assembly, a first filter valve, a second filter valve, a micro differential pressure detector and a filter absorber, wherein the first cleaning valve, the second cleaningvalve, the three-proofing machine, the three-way box assembly, the first filter valve, the second filter valve, the micro differential pressure detector and the filter absorber are arranged in the cabinet body; air filtration and ventilation equipment, the ventilation and conversion control system are integrated into a whole, the performance is efficient and reliable, and the assembly is convenient; automatic ventilation operation at ordinary time and working time of small protection engineering is achieved; various toxic agents can be effectively removed in the attack of the nuclear and biochemical weapon; the detection, the automatically converted operation modes, state display function is integrated, the intelligent degree is high, and the operation is convenient; the double-power-supply power supply is adopted, so that the operation is reliable.