Abstract: This paper expounds the importance of in-situ observation of rock-and-soil. It reviews the evolution history of the in-situ rock-and-soil observation technology. The rock-and-soil observation technology can be divided into five categories,namely survey,remote sensing,testing,exploration and monitoring. The characteristics and shortcomings of these five categories of observation technology are discussed respectively. Based on this,the concept of multi-field sensing of rock-and-soil is further expounded. The connotation and characteristics of multi-field sensing technology are discussed emphatically. It is concluded that the time-space continuous sensing technology is a new paradigm of in-situ rock-and-soil observation in the field of geological and geotechnical engineering. Finally,the distributed fiber optic sensing technology and its application to realize multi-field sensing of rock-and-soil are briefly introduced.