The invention provides a medium processing mechanism and a financial self-service terminal. The medium processing mechanism comprises a frame, a medium separating mechanism, a medium collection mechanism, a baffle plate, a separation plate and a compression plate, wherein the baffle plate, the separation plate and the compression plate are sequentially arranged in a linear manner. The baffle plate, the separation plate and the compression plate can slide on the frame in an arrangement direction, and also get close to or leave the baffle plate. The top of the baffle plate is provided with a first accommodation groove, and the first accommodation groove is opened towards the top of the baffle plate and the separation plate. The top of the separation plate is provided with a downward recessed part, and the downward recessed part is corresponding to the first accommodation groove. When a medium is located between the separation plate and the baffle plate, the bottom of the first accommodation groove and the bottom of the downward recessed part are lower than the top of the medium. When a first accommodation space is communicated with a medium separation mechanism, a second accommodation space can be communicated with medium collection mechanisms at the same time. The medium separation and collection operation cannot affect each other, thereby improving the medium processing efficiency. The first accommodation groove and the downward recessed part facilitate the taking of the medium, and enables the application to be convenient.