论述了开发拖拉机机组系统性能CAD研究开发工作的现状和必要性 ,根据机组CAD软件系统特点和功能要求 ,从软件应用领域、软件规模、数据类型和混合编程等方面 ,阐述了软件开发过程中软硬件系统的选择原则。根据原则 ,为软件系统开发选择了语言环境和硬件培植 ,对软件系统平台进行了设计 The status quo and necessity of developing CAD system for research and development of tractor unit system are discussed. According to the characteristics and functional requirements of unit CAD software system, the software and hardware, hardware and software are expounded from the aspects of software application, software scale, data type and mixed programming. System selection principle. According to the principle, chose the language environment and the hardware cultivation for the software system development, designed the software system platform