The invention belongs to the field of folding doors, and specifically discloses a flat folding door system. The flat folding door system is characterized in that the flat folding door system comprisesa support frame, a folding door body, a transmission device, a speed control device, a pressing device, a sliding guiding device, and a supporting transferring device, wherein the folding door body,the transmission device, the speed control device, the pressing device, the sliding guiding device, and the supporting transferring device are arranged on the support frame; the folding door body is driven by the transmission device to open or close, the speed control device is used for controlling the opening or closing speed of the folding door body, and the pressing device is used for pressingthe folding door body to prevent the vibration of the folding door body; and the sliding guiding device and the supporting transferring device are used for guiding and supporting the folding door bodyduring the opening or closing of the folding door body correspondingly. The flat folding door system has the advantages that the structure is compact, operability is good, the anti-vibration structure is adopted, the large inertial impact generated during high-speed movement and emergency stop can be resisted, and stable opening and long-term using of a door body can be ensured.