The invention relates to a special-shaped waterway mold forming mechanism capable of avoiding waterway powder compaction. The special-shaped waterway mold forming mechanism comprises a forming box, aforming lifting air cylinder and a forming lifting block; the upper part of the forming box is provided with a laser transmitter which is matched with the forming lifting block and connected to a controller; a powder feeding inlet and a powder discharging outlet are formed in the side face of the forming box; the side, opposite to the powder discharging outlet, of the forming box is provided witha scraping air blowing device; the scraping air blowing device comprises a scraping movable device and a scraping block connected with the scraping movable device; the scraping block is a cavity blockwith the lower part open, and an air blowing mounting block is arranged in a cavity; air blowing spray heads which downwards blow air are mounted on the air blowing mounting block side by side in thefront-rear direction; and the air blowing spray heads communicate with an air blowing pump on the outer side of the scraping block through air blowing pipes, and the air blowing pump is connected tothe controller. Through the design of the scraping air blowing device, after each layer of sheet body is formed, unformed powder in a waterway can be air-blown to be dispersed, the compacted state ofthe powder in the waterway is changed, and thus subsequent clean-up is convenient.