Abstract: For the maximization of the efficacy of the polycrystalline diamond compact (PDC) bits in drilling engineering, comprehensive research, including theoretical analysis, laboratory test, case study, and on-site trials, was conducted to investigate how a high weight-on-bit (WOB), a high rotary speed, and other optimized drilling parameters work on the rate of penetration (ROP) and the wear of a PDC bit. Furthermore, the wear mechanism of the PDC bit and the primary cause of the premature failure of the bit were analyzed. The results indicated that: 1) The ROP of the PDC bit was directly and primarily affected by the WOB. When the bit was in an efficient rock-breaking state, the WOB was invariably in a linear relationship with the ROP whether the formation encountered was a conventional one or a hard rock formation. Adding a high WOB over 200 kN into the normal pressurization range of the PDC bit was recommended if the formation encountered was a homogeneous hard rock formation. 2) ROP improvement could be achieved by enhancing the rotary speed. Although the wear of the PDC bit could be aggravated by a high rotary speed, the requirement on a PDC bit to penetrate most formations for a long time at a high rotary speed (400–500 r/min) could be readily met by the quality of the currently available PDC cutter. 3) The ROP of the bit was also affected by cutter density, but not in a direct manner. As long as a dynamic balance among “capabilities to bite into the formation, cut the rock, and evacuate the cuttings in time” was reached, the optimized fast drilling could be achieved even by a PDC bit with a high cutter density. 4) The wear of the PDC bit was less severe under the higher rock-breaking efficiency of the bit. The WOB could be enhanced to improve the ROP and reduce bit wear. 5) Dynamic impact and inefficient rock-breaking were considered the primary causes of the premature failure of the PDC cutter and bit. The key for the PDC bit to achieve efficient penetration was improving rock-breaking efficiency and restraining bit vibration. The above results could be used as a reference for the proper utilization of PDC bits and the innovation of ROP improvement technologies.