China is rich in hot dry rock resources which has a high utilization factor and can provide a stable base load for electricity. It is considered to be a renewable and clean energy capable of shouldering the important task of energy revolution. Its large-scale development is key to achieve "carbon peak and carbon neutrality". However， after nearly half a century， only a small number of hot dry rock demonstration projects of EGS in the world have a little power generation， and there are still many technical bottlenecks in achieving the goal of industrialization. By studying the EGS development process and drilling fluid technology， the author proposes that there is drilling fluid loss during EGS drilling. Therefore， the components of the drilling fluid itself， the drilling fluid and cuttings or the rock on the well wall， the drilling fluid and the surface rocks of the reservoir， will undergo various physical and chemical reactions under high temperature and high pressure to generate new substances. These new substances may precipitate on the well wall， and may even be consolidated with the well wall or the surface of the fracture. This reduces the effective space of the fracture， or even seals the fracture， and is difficult to remove； thus， decreasing the reservoir permeability greatly and leading to difficulty in gain the flow rate for power generation. Therefore， it may be a technological breakthrough in the industrialization of hot dry rock to innovate the concept of drilling fluid technology， study the relationship between drilling fluid components and cuttings and temperature and pressure under EGS environment and their influences on drilling fluid performance， and precisely predict and control the drilling fluid performance， the flow characteristics of the drilling fluid in the wellbore， and the compatibility of the drilling fluid with the reservoir rock with advanced computer data statistics， analysis and calculation techniques so as to avoid or reduce the loss of the drilling fluid and the reaction of the drilling fluid with the rock， and eliminate the reservoir damage and increase permeability.