With the continuous development of the exploration， development and utilization of deep mineral resources， the bottom environment of the hole is more complex. Pregnant diamond bit， as a special tool for geological drilling， the complex deep hard rock geological environment also puts forward higher requirements for the performance of pregnant diamond bit. The efficiency and life of crushed rock of pregnant diamond bit are closely related to the performance of broken rock unit. This paper summarizes the research status of drilling wear response of pregnant diamond bit in deep hard rock drilling. At present， the research is not perfect， so further in-depth analysis is needed to clarify the response mechanism. On this basis， discusses the innovation of broken rock unit in recent years， the emphasis from the internal structure and the analysis of different reinforcement way of the cutting unit strength， wear， drilling efficiency， the results show that it can effectively improve the deep hard rock pregnant drill cutting efficiency and working life. From the perspective of prolonging lifespan and increasing efficiency， this paper discusses the direction of strengthening the broken rock unit of impregnated diamond drill bits suitable for deep hard rock drilling， providing reference for the design and manufacturing of impregnated diamond drill bits for deep geological drilling.