Abstract: It is essential to develop quality geological CAI application software for teaching purpose. Here we present a course ware of Computer Aid Instruction for Structural Geology (SGCAI), which includes a large capacity of database, cartons and multimedia technique. The SGCAI can be used in theory geological courses. It constructs a properly module structure with a friendly interface and hence is easy to operate. The SGCAI is of full functions, in which teaching management and data processing functions are quite new and practical in operation. With the (environment of) SGCAI, students can fully take their initiative. The SGCAI is a new tool to improve teaching quality and train composite geological personnel for the 21st century.