With the rapid development of information technology, computer technology has been getting more widely used in daily life, thus, it is necessary for each university graduates grasp basic technical skills of computers. However, usually a teacher will be responsible for teaching many college students basic computer courses, so it is difficult to ensure the quality of the teaching with the enlarged students' enrollment. In this paper we propose combining data mining and online examination system to improve teaching of basic computer courses, and discuss this issue in detail.