The invention discloses a control protection method for achieving a deicing function of a direct-current deicing device. According to the control protection method for achieving the deicing function of the direct-current deicing device, when the direct-current deicing device is in a wire deicing mode, the one-going-one-back deicing mode or the one-going-two-back deicing mode is adopted, and fixed direct current is adopted by the direct-current deicing device to serve as a control target at the moment. When the direct-current deicing device is in an overhead ground wire deicing mode, a third switch and a fourth switch are controlled to be at the positions of opening all the time, the opening and closing positions of a first switch and a second switch are controlled according to the rules, the direct-current deicing device uses fixed ground direct current as a control target, deicing circuit ground protection is canceled, and ground current overcurrent protection is added. When the control protection method for achieving the deicing function of the direct-current deicing device is used, the requirement for carrying out earth backflow deicing on an overhead ground wire can be met under the situations that the primary equipment structure of an original direct-current deicing device is not changed, and only a control protection system is modified.