Aimed at the characteristics of complex flow, data shortage, and protected object of Aibugai River basin,the paper coupled 3S technology with hydraulics to research flood control scheme in the downstream of reservoir，and built the regional model in downstream chanel of Talinggong reservoir of Aibugai river and its two sides coupled with HEC-RAS based on ArcGIS platform, real-time loading of remote sensing images.It simulated the flood routing in the downstream after the operation of natural floods and. And then,it determined the actual flood protection ability of the channel. Based on the results of simulation, the general layout of flood control project was determined. The flood protection scheme was determined through comparing the total investment of different programs which is that after the operation of peak-alternation of the reservoir ,to open the spillway and spillway gate for free discharge.The reservoir does not increase the flood storage and the downstream of reservoir is separately repaired and the new dike is built.