The invention discloses a deep well grounding electrode for UHVDC transmission, comprising a first grounding electrode and a second grounding electrode connected with each other. The first ground electrode comprises a first ground electrode lead wire coated with an insulating layer; a first protective wall, which is an insulating protective wall, wherein a first ground electrode lead is arranged in the first protective wall; a first filling layer arranged in the first protective wall, which is an insulating filling layer. The second ground electrode includes a second ground electrode lead connected to a lower end of the first ground electrode lead; a second protective wall, which is a conductive protective wall, and a second ground electrode lead is arranged in the second protective wall;a second filling layer arranged in the second protective wall, which is an electrically conductive filling layer. The lower edge of the first grounding electrode is buried in the soil resistivity greater than 200 omega.m, and the lower edge of the second grounding electrode is buried in the soil resistivity less than 100 omega.m. The deep well grounding electrode solves the problems of DC magneticbias of transformer and corrosion of buried metal caused by grounding current of grounding electrode.