For the MMC-HVDC transmission line after the faulty trip, there is no coupling relationship between the line integrity pole and the fault pole, which makes the reclosing criterion based on characteristics of induced electrical quantities are difficult to apply. Thus an adaptive reclosing strategy for MMC-HVDC transmission lines based on the characteristics of additional capacitor discharge voltage variation is proposed. The additional capacitor is switched on after the DC line trips to construct the mathematical model of the additional capacitor discharge and then analyze the difference of the characteristics of the additional capacitor discharge voltage when there is fault and the fault disappears. Combined with the difference, a new criterion for fault property identification of the flexible DC line is designed to determine the permanent fault or the transient fault. Based on the fault characteristic identification method, the reclosing of the line is realized. Finally, the circuit model is built based on PSCAD/EMTDC to verify the validity and reliability of the adaptive reclosing strategy of the MMC-HVDC transmission line. This work is supported by National Natural Science Foundation of China (No. 51877185).