A connection assembly of the photo-conductor drum is applied for linking a driving shaft. The connection assembly of the photo-conductor drum includes a drum gear and a connector. A first connection part arranged at an end of the drum gear. An end of the connector forms a second connection part corresponding to the first connection part. Another end of the connector forms a joint end. The joint end includes a central pillar, and a plurality of protrusions extending from a periphery of the central pillar. The second connection part could detachably connect to the first connection part. The joint end is detachably connected to the driving shaft. Therefore, by replacing the damaged drum gear or damaged connector only, the costs, quantity of the waste and the maintenance expend would be reduced.