Abstract: In this paper, functional construction, development tendency, and several key problems of hardware technique in automatic monitoring system on geological engineering project are discussed. The authors put stress on the key problems of hardware technique in development of automatic monitoring system on geological engineering project. A example of automatic monitoring system setup for a large hydropower station slope mainly by the authors is introduced. For the system a lot of difficult problems were solved, such as thunder shock protection both in monitoring instruments and in the installed transducers, high precision modulation of special transducer signal in a very small module, etc.