From the point of connection ingineering of river,lake,reservoir and main water system in Haikou, lakes and reservoirs, the paper summerized the water resources system of Haikou,and compared the difference of result of water resources before and after the connection engineering of key water system was completed.This paper considered the allocation goal of three location as a whole of water resources quality and benefit and built a allocation model of water resources of Haikou1.It discussed the present situation and future of the balance between water resources supply and demand.The result showed that there are imblance problem of water resources supply and demand in every region of Haikou.The construction of connection project of water system can greatly alleviate the regional shortage problem of water resources.