The early warning for water supply of reservoirs has important theoretical significance and practical values for the comprehensive utilization and sustainable development of water resources. Jinxiuchuan reservior is an important drinking water source in the southern mountain area of Jinan, the establishment of its early warning system is more necessary. In this paper, the monitoring and service platform of Jinxiuchuan reservoir were established using the advanced technology of the internet of things. The MIKE11 HD river simulation software was selected to simulate the processes of water supply and utilization in different operating conditions. Through the analysis of the change rule of water level and flow, combined with the practical situation of reservoir and the platform function of the internet of things, the effective early warning system for water supply was established. It will be supportive in rational utilization and optimal operation of reservoir water resources.