Using the photomultiplication (PM) effect to enhance the external quantum efficiency of the device is a significant way to realize high-sensitivity organic photodetectors. This review introduces the research progress of PM-type organic photodetectors in recent years based on charge accumulation-type PM. The strategies for achieving PM and the corresponding PM mechanisms are clarified in detail from the perspective of the methods of implementing charge accumulation. Furthermore, the future research of the PM-type organic photodetectors is prospected.