This article uses the digital phase-lock frequency synthesis technical to design entire digital and high accuracy frequency source, this frequency source mainly uses the digital phase-locked loop and AT89C52 microcomputer.It's output frequency is adjustable in the 0Hz~9999Hz scope smooth, the frequency source may the manual establishment output frequency, and has time the power failure or engine off's frequency memory function, the frequency source may demonstrate this frequency during output frequency. The frequency source's frequency value may also by the PC, the PC use the software of Kingview for long-distance monitoring frequency source .