Abstract: Geological hazard monitoring and monitoring system are outlined in this paper. Geological hazard monitoring system should have functions of digitalization, automation and network.The characteristic information prior to geological hazards is transformed digitized information by transducer to transmit and store it.The experimental study of displacement transducer and an application of deformation monitoring system to Lianziya danger rock in the Three Gorges on the Yangtze River are given in this paper also.