Based on the runoff data of three inland rivers from the control hydrologic stations for mountainous runoff(Zamusi,Yingluoxia,Changmapu) from 1956 to 2006,the numerical method,Mann-Kendall nonparametric test,Hurst index analysis methods were used to analyze the annual variation of runoff in recent 50 years.The results showed that there was marked runoff change in record series but in different years;Shiyang River had a decreasing tendency especially in the 1990s,runoff of Heihe River and Shule River were in...