A dedusting filter bag having an optical detection function is disclosed. The dedusting filter bag comprises a controller, a wireless signal emitter, a mounting plate, a cage fixed to the mounting plate and a filter bag main body sleeving the cage. The mounting plate has a central hole. The cage includes a plurality of parallel vertical ribs surrounding the central hole. The plurality of vertical ribs include a first vertical rib and a second vertical rib. A first cross bar, a first plane beam splitter, a second plane beam splitter, sheet glass and a second cross bar are connected between the first and second vertical ribs in order from bottom to top. The first and second plane beam splitters are parallel to each other. The angle between the first plane beam splitter and the horizontal plane is 45 degrees. First and second light intensity sensors are fixed to the first vertical rib. A laser emitter is fixed to the first cross bar. A third light intensity sensor is fixed to the second cross bar. The filter bag can detect whether the filter bag is broken or not and the breakage situation.