Abstract: After being studied by size statistics in Changma diluvial fan, the conclusion that sediments sizes were largened 7 times from Early Pleistocence was drawn. That is to say, the north-eastern margin of the Tibetan plateau has uplifted 7 times. The same conclusion also had been drawn by analysising the sediments of basin and active fault and the river terraces. They have the same active times with the Tibetan plateau uplift in sera. So, the size statistics given a new methed to study the diluvial.