This paper focuses on the high reliability design of power supply for carrier communication circuit from over-current and shortcut protection and ripple suppression. Compared with the DC/DC and LDO protection circuit, the circuit designed by this paper not only has the over-current and shortcut protection function, but also with undervoltage protection, greatly improves the reliability of the circuit and reduces the power consumption under the protection state to achieve low power consumption.The LC filter by using the butterworth low-pass filter normalized design, is used to reduce ripple voltage and improve capacity of resisting disturbance. From the test results can be seen, the circuit designed by this paper works well, and has been tested by State Grid metering center.