Commutation failure, DC blocking and near AC short-circuit fault of HVDC transmission system would lead to transient overvoltage of sending-end power grid, restrict transmission capacity and threaten safe and stable operation of system. For this reason, this paper firstly gives the similarities and differences of the transient overvoltage generation mechanism of DC sending-end power grid under three typical fault conditions of commutation failure, DC blocking and near-field AC fault are analyzed systematically, and the main influencing factors of transient overvoltage are clarified. Secondly, the existing transient overvoltage suppression strategies and their advantages and disadvantages are summarized. Finally, in view of the shortcomings of the existing research, it is analyzed that the three aspects of analyzing the transient overvoltage mechanism of different new energy transmission scenarios, revealing the coupling law of multiple influencing factors of transient overvoltage, and constructing a multi-temporal and spatial scale transient overvoltage collaborative suppression system are the focus of future research on transient overvoltage of HVDC sending-end power grid.