Based on analysis of regional runoff variation regularity and future tendency of Heihe River Basin,it is concluded that there is little annual change of runoff caused by from mixed compensation of rainfall,glacier melting and groundwater.It is favorable for utilization of water resources in the region.While annual distribution of runoff effected by monsoon climate,and water and heat condition is same,it is a very favorable condition for agricultural irrigation.However,in the spring rainfall is seldom,the draught of block situation appears quite often.The record shows that the tendency of water in the past50years tended slowly increasing in the fluctuating and it will be so in future10years.The suggestions of regional water resources optimum allocation are presented by the author for water requirement of sustainable development of society and economy in middle and lower reaches of Heihe River.