The present invention relates to an HVDC thyristor-level direct current voltage equalizing resistor dynamic parameter online monitoring method. A device used in the method is an HVDC thyristor-level direct current voltage equalizing resistor dynamic parameter online monitoring device comprising a triggering monitoring plate and a serial direct current voltage equalizing resistor-thyristor unit which are connected to each other, wherein the direct current voltage equalizing resistor-thyristor unit is formed by a direct current voltage equalizing loop and a thyristor which are connected in parallel. Current collection nodes are arranged at a cathode of the thyristor, a voltage of a connection point of the direct current voltage equalizing resistor and an anode of the thyristor is obtained through calculation according to a direct current control protection system triggering command, and an average value is obtained through multi-time sampling calculation at different moments to obtain voltage equalizing resistor parameters. The HVDC thyristor-level direct current voltage equalizing resistor dynamic parameter online monitoring method converts a detection work requiring interruption maintenance to real-time detection of a device in a daily operation to shorten invalid maintenance time, and converts 'periodic maintenance' of a conventional substation device to 'state maintenance' ofa conventional substation device to improve a use ratio of a converter valve while improving a prevention means of fault generation of the converter valve.