In view of the drilling rod broken accident that often occurs in geological drilling, in this article, the main factors that lead to the wire-line drilling rod breaking are analyzed in the aspects of drilling rod material and processing, complex formation conditions and drill hole bending, and the corresponding prevention measures are summed up in drilling rod material selection, drilling rod processing and heat treatment process, thread structure optimization and fine processing, borehole structure and drilling tool grading optimization, wall protection and leakage plugging technology and field operation regulations. It is suggested that the drilling tools grading and drilling regulation parameters should be optimized by numerical simulation to strengthen the detection of drilling rod corrosion defects and crack, so as to improve the reliability of the whole drilling system.