In this paper, through using Pro/Toolkit to do secondary development of Pro/E, it completes the parametric modeling of every key parts of rice and wheat combined harvester chassis by using the object-oriented technology, and combines with Microsoft Access database to store the relevant knowledge. Meanwhile, it collects lots of related knowledge about rice and wheat combine harvester chassis from various channels and establishes a knowledge base of key components of the chassis after sorting them which can achieve the purposes of rapid designing chassis.