Ice coating on transmission lines will endanger the safe and stable operation of the power system. High-frequency excitation ice melting is a new type of de-icing method,which has the technology forward positions development of de-icing online. The high-frequency excitation power supply is the core device of the de-icing technology,in this paper, a 5kHz high-frequency excitation de-icing power supply for ice-covered lines is studied. High-power output is realized by series H-bridge power unit modules, and carrier phase shift modulation technology is used to reduce the switching frequency and increase the output voltage and power of the inverter. A control method of adding a voltage amplitude outer loop based on double closed loop control is proposed, which effectively improves the dynamic performance and stability of the system, eliminates the system static difference, and obtains a good output waveform. The simulation verifies the feasibility of high frequency excitation power supply design and its control method.