The invention discloses a ceramic flat membrane, which comprises a membrane layer, a transition layer and a porous supporting layer, wherein the porous supporting layer comprises a buffer layer, another buffer layer and a supporting component; the upper surface of the buffer layer and the lower surface of the another buffer layer are both provided with embossments and dents; the supporting component is arranged between the buffer layer and the another buffer layer; the upper surface of the another buffer layer is provided with the transition layer; the upper surface of the transition layer is serrated; the membrane layer is arranged on the upper surface of the transition layer; the lower surface of the membrane layer is provided with a serration matched with the upper surface of the transition layer. The ceramic flat membrane has the beneficial effects that the supporting component is added at the porous supporting layer; the use strength at a high temperature and under high pressure is improved; a contact surface of each layer is arranged to be in a circular-arc shape; a cleaning dead angle is avoided and the damage by acid and alkaline corrosion is lightened.