When a roadheader breaks hard rock in a roadway, the excessive cutting load causes the conical pick to experience abnormal wear, which impacts equipment stability. To improve the reliability of hard rock cutting equipment, the dynamic characteristics of prefabricated grooved rocks during cutting were investigated using a single pick cutting experimental bench in rock crushing experiments, and a conical pick cutting rock breaking finite element model was established. The rock stress state under different cutting depths and spacing conditions was analyzed, and the cutting force and the trend of the change in the specific energy consumption were elucidated. The results show that prefabricated grooves can effectively reduce the cutting load and specific energy consumption, the cutting depth and conical pick–groove spacing are the key factors affecting the cutting characteristics, and a reasonable choice of spacing and depth can help reduce the wear of conical picks and improve the working reliability of roadheaders.