One Strong-motion Monitoring System For Dam-reservoir Strong Motion Observation Was Introduced In This Paper. This System Includes Three Parts, Strong-motion Monitoring Devices, Power Supply Instrument, Communication Devices And Strong-motion Monitoring Software. It Can Measure Dispersed Earthquake Signals And Collected Data To One Point. And Also Measure The Level Of The Water Available In The Dam. Beijing Miyun Dam Reservoir Strong-motion Monitoring System Based On This Technology Was Illustrated In This Project.