This paper introduces the application of composite drilling technology of rotary （top drive） drilling and PDM drilling in hot dry rock Well-GR1 in Gonghe Basin， Qinghai so as to improve hot dry rock drilling efficiency and reduce downhole incidents. According to the working characteristics of the PDM drill under high downhole temperature， optimization was conducted of the high temperature resistance rubber， as well as the clearance between the stator and rotor of the PDM drill. It was tested for drilling of the high temperature hot dry rock well （hole depth of 3705m， hole bottom temperature 236℃） for the first time and was successful. It can provide experience for hot dry rock drilling and deep geothermal resource exploration.