The grounding technique is one of the key technologies to ensure reliable operation of power electronic devices, and a series of grounding questions are studied. The classification, definition and purpose of grounding are described, the concept of grounding impedance is introduced to explain various grounding phenomena appeared, and the solving strategies for the grounding problem are presented. Finally, a better grounding technology scheme is designed for practitioners to solve most of the grounding technology problems in the power electronics technology practical applications.