Abstract: In response to the problem of voltage fluctuation of the converter busbar at the sending end caused by the commutation failure in the high-voltage direct current transmission system, the mathematical relationship between the voltage of the converter busbar at the sending end and the DC voltage and DC current at the rectifier side is first derived. It is concluded that the main reason for the voltage fluctuation of the converter busbar at the sending end is the uncoordinated change of the DC voltage and DC current during the commutation failure and recovery period. To suppress voltage fluctuations in the converter bus, based on quantitative analysis between the reactive power consumption of the rectifier and the voltage, the expected value of the reactive power consumption of the rectifier is determined using the converter bus withstand voltage level as a constraint. Combined with the analysis of the rectifier′s reactive power characteristics, the compensation amount for the direct current command value during communication failure and recovery period is determined. A voltage fluctuation suppression strategy based on rectifier reactive power control is proposed. Finally, the correctness of and of the effectiveness of the voltage fluctuqtion suppression strategy are verified based on the PSCAD/EMTDC simulation platform.