By analyzing the drop of the second side voltage， the back corona and the inner sediment dust of the 450 m 2 sinter in TISCO， the efficiency of the dedusting system has been improved effectively through a series of measurements accordingly. The scientific disposal of the tiny dust in the end electrical field is provided， thanks for the study of the dust grain size from the main dedusting system. As the effect， less than 50 mg/m 3 dust emission of the main electrical dust collector in TISCO has been achieved.