The invention relates to a flat-plate photobioreactor device system. The flat-plate photobioreactor device system comprises a photobioreactor body, an aeration system, an algae liquid circulation system and a spray system, wherein the photobioreactor body comprises a reactor shell, a spray area and reaction areas; n stages of reaction areas are available, n is greater than 1, the n stages of reaction areas are partitioned by inner partition boards, and space is reserved between the inner partition boards and the bottom of the reactor shell, so that algae liquid can enter each reaction area from the spray area; flow guide plates are arranged in the reaction areas along the flowing direction of the algae liquid, and are positioned in the central positions of the reaction areas; space is reserved between the flow guide plates of the n stages of reaction areas and the top of the reactor shell. The flat-plate photobioreactor device system has the beneficial effects that the large-scale application of the microalgae carbon fixation technology can be realized, the problems that the traditional stirring mixing method is poor in mixing effect, and the shear force generated by stirring can severely damage the cellular structure of the microalgae are solved, the sufficient mixing of CO2 and the algae liquid in the photobioreactor is guaranteed, and the CO2 mass transfer rate is improved.