This paper analyses the PCI bus features, and introduces several developing tolls and the techniques, including PCI controller IC, driver development software and the key points of designing PCI cards with the main focus on IC S5933 and driver development software WinDriver. An example in the virtual instrument-a random signal generator, consisting of PCI card and software, is also given. DDS is realized by software, through the high transfer speed of PCI bus. The signal generator can produce sin, noise, frequency sweep and others complex waves. It can be used to adjust the wave, frequency, amplitude, phase and precision conveniently and accurately.