A powder filtering mechanism includes a connecting part, a main body, a duct, a suction device and a bracket. The connecting part is in communication with a powder inlet. Moreover, plural filters are disposed within an accommodation space of the main body. The suction device is in communication with the main body. The bracket supports a micro-particle adsorption structure. During operation of the suction device, flying dust of excess construction powder is inhaled into the powder inlet, and a portion of the flying dust is transferred to the accommodation space. After the portion of the flying dust is filtered by the plural filters in multiple filtering steps, micro-particles of flying dust passing through the plural filters are transferred to the micro-particle adsorption structure so as to be adsorbed by the micro-particle adsorption structure.