Abstract: After the extra large scale debris flow hazards in Sanyanyu valley of Zhouqu county on August 8,2010,Study on its future development trend is the basis of accomplishing post-disaster reconstruction in Zhouqu and disaster prevention and reduction.After field investigation and historical date collection,analyzed the possibility of recurrence about debris flow in Zhouqu and its future development trend.Studies suggested that it still has the possibility of debris flow in Sanyanyu valley.The topography and rainfall conditions for debris flow in Sanyanyu valley are still exist.A large amount of loose deposit still accumulated inside the valley.The discharge volume of the extra large scale debris flow on August 8,2010 are only 180×10⁴m³,and it is 1/15 of total material source.The debris flow in Sanyanyu valley is still developing with greater frequency and scale.Losses caused by debris flow could be decreased by reduced the residents,housing and infrastructure on debris flow accumulation area.