在ASIC设计中常常会用到双向IO口来节省系统的硬件资源。但很少有书籍对INOUT口的程序设计和仿真进行介绍，同时，一些书籍介绍的方法在实际中无法使用，本文通过一个图象传感器的事例来详细说明INOUT口的设计方法，并提出一些与实际情况相符的仿真方法-In ASIC design often used in bi-directional IO port to save the system s hardware resources. However, very few books on INOUT mouth design and simulation procedure is introduced, at the same time, a number of books to introduce the method in practice can not be used, the paper through an example of image sensor to a detailed descr iption of the design method INOUT mouth and put forward some actual position in the simulation method