This paper presents an approach for building an analog SPICE behavioral model based on the information provided by IBIS model. Such analog SPICE behavioral model can describe both static and dynamic characteristics of I/O buffers. The method to extract dynamic information from IBIS switching waveform VT tables is discussed in detail. Two types of models can be generated depending on the availability of the waveform tables with different load conditions in IBIS data. The influence of waveform table load condition on the validity of the analog SPICE behavioral model is also investigated.