Abstract: This article introduces a kind of designing method that adopts AT89C52 to control the device as the core and uses digital wave synthetic technology to produce square wave,triangular wave,saw tooth wave,sinusoidal wave and other period function signal wave.The frequency range is in 0.001Hz～999.9Hz,the amplitude is adjustable in succession as no grade in 0～20V,wave distortion:<0.5%.It is good in stability,excellent in the performance and convenient in operation and has high value in application.