The utility model discloses a dust removing system for preparation of an aromatic hydrocarbon reaction product gas from an organic oxide through catalytic conversion. The dust removing system comprises at least one group of a first-stage cyclone separator (2) and a second-stage cyclone separator (3) which are arranged at the upper part in a cavity of a reactor (1) and connected with each other in series; the dust removing system further comprises a third-stage dust remover (4) which is arranged outside the reactor (1) and communicated with the second-stage cyclone separator (3), the middle part of the third-stage dust remover (4) is a straight cylinder section, and a dust removing inner member (7) is positioned in a space formed by the straight cylinder section and a shell at the top of the third-stage dust remover. By adopting the dust removing system disclosed by the utility model, the operating cost of a device for producing aromatic hydrocarbon from the organic oxide through catalytic conversion can be lowered, meanwhile, the abrasion of subsequent product gas cooling and separating system equipment and pipelines can be alleviated, and the operating period of the device is prolonged.