A panel light apparatus includes a base plate, a light source, a frame and a light passing cover. The base plate has a fixing unit for fixing the base plate to a platform. The base plate has multiple rotation units to switch between a lock mode and a release mode. The light source is disposed on the base plate. The frame has multiple attaching units to attach to the rotation units in the lock mode for fixing the frame to the base plate. The multiple attaching units are released from the rotation units in the release mode. The frame has a light opening. The light passing cover attached to the frame for covering the light opening for a light of the light source to pass through.