Drought limit flow is a hydrological characteristics index to evaluate river dry levels and an important basis to start the response level of drought emergency and to do a good job in drought water emergency scheduling.The paper calculated the intake discharge by analyzing the water demand of hydrological downstream cross section. Taking the sum of intake discharge and channel ecological discharge as the initial value, the drought limit discharge was comprehensively determined. Based on the analysis of drought limit flow in the main control section of Weihe River basin, the drought limit flows of tuoshi, Weijiabu,Xianyang,Litong,Huaxian are 6.0,1.0,0.0,0.0,2.0m3/s,the result can provide reliable basis for the scientific , reasonable judgment of hydrologic drought level and drought relief command decision.