The invention provides an online detection mechanism for a ceramic tile polishing machine. The online detection mechanism comprises a conveying component used for conveying ceramic tiles; an installing frame of the conveying component is provided with a plurality of connecting rods which are arranged side by side in the width direction of the conveying component; the connecting rods are installed on the installing frame movably; one end of each connecting rod is provided with a pressed part, and the pressed parts are in contact with ceramic tiles and are pushed and pressed by the ceramic tiles, so that the connecting rods move relative to the installing frame; the other end of each connecting rod is provided with a trigger part. The online detection mechanism for the ceramic tile polishing machine also comprises a detection unit used for detecting the positions of the trigger parts. The online detection mechanism can perform breakage detection on internal ceramic tiles in the working process of apparatuses and prevent the problem that ceramic tiles break in the apparatuses and affect the apparatuses; the plurality of connecting rods are arranged side by side in the width direction of the conveying component, so that the pressed parts of the connecting rods can be in large-scale contact with ceramic tiles and large-scale breakage detection can be performed on the ceramic tiles when the ceramic tiles are conveyed in the length direction of the conveying component.