Reform of practical teaching driven by practical training with real projects is a reform to improve every aspect of practical teaching by introducing, processing and decomposing real world projects to create real cases for teaching. In this article, the current reforming process of practical teaching in the area of computer science is analyzed from the point of view of a constructivist. In regard of the characteristics of the educational system in computer science, we also discussed how to organize and implement such enterprise-level project-driven practical teaching under the guidance of constructivism theory.