Abstract: The natural exhaust system in screw type dryer often resulted in higher and fluctuated moisture content in dried scraps,therefore it was replaced by a mechanical exhaust system.After improving,the daily values of average,maximum and minimum moisture content of dried scraps were within the range specified by the technology norm(11%-13%),and the daily absolute moisture content difference was not over 1.2%.The moisture exhaust ability of the screw drier was enhanced by the mechanical exhaust system,moreover,it did not affected by environmental conditions,and the drying quality of scraps was improved.