A powerless diversion plate of a ceiling air-conditioning circulation machine includes a bearing block and a bearing within a circular inflow/outflow hole for installing a diversion disc having a plurality of radial separation pieces. A plurality of conic and ring-shaped diversion pieces are positioned around the connection shaft. The diversion disc is separated by the ring-shaped diversion pieces and the radial separation pieces to create air inflow/outflow zones. The diversion disc has a downward protruding middle part and a staged structure at the rim thereof to form a predetermined shape. This obviates a powered motor, as the radial separation pieces of the diversion disc serve as a working surface, and respond to forced air for causing the diversion disc to be driven in 360° rotation to diffuse air downward or suck air upward in a flowing way, thereby enhancing air-outflowing and convection efficiency and reducing energy consumption and carbon release.