Abstract: The arbitrary waveform signal generator board based on PC bus was designed. The board adopts big capacity memorizer, automatic scanning circuit and the 16 bit digital-to-analog converter, and can export arbitrary waveform without occupying system resources. The paper analyzed the theoretical error to output waveform, improved output waveform precision, and gain the law of sample point amount and scanning frequency to waveform precision. It is proved by experimentation that the board can output accurately all kinds of waveforms. The frequency band of the output signal is from 10^-5 Hz to 200 kHz with an amplitude precision of 2 mV. While the frequency precision is 99.51% when sample point is 200. The board can be widely used in virtual instruments.