In order to realize the fast and accurate location of breakdown point of grounding electrode line caused by a HVDC unipolar fault, and shorten the power supply restoration time, a fault location method for grounding electrode line based on fault recorder of converter station is proposed. Theoretical analysis has revealed the relationship between the oscillation frequency of the neutral bus in the converter station UDN and the grounding electrode line inductance, combined with the line model and considering the effects of frequency dependent characteristics, a fault location algorithm based on the quantitative relationship between frequency, inductance and distance is proposed. Practical fault cases of a UHVDC project from Southwest to East China is used to check the method. The results show that the method is effective and accurate, and it does not need to increase the configuration of hardware and software of converter station, so it is convenient for engineering application. This work is supported by Youth Science Fund of National Natural Science Foundation of China (No. 51707019) and China Postdoctoral Science Foundation (No. 2016M592659).