Abstract: In order to enhance the automation degree of underground water level observation, this paper designed underground water level dynamic monitoring system.Making the AT89S52 as the key part, the hardware circuit of this system includs sensor, analog-digital converter, storage, display module, interface circuit and so on.The lower computer of the system adopts single chip C language programming and the upper computer adopts VC++programming.Verified by debugging, the operation of the system is stable, reliable and achieved the design requirements.