In this article, the authors provide a new approach to massive open online course: project based case learning. Although there are many online teaching websites, such as Coursera and Edx, most of the courses are video based. That is, students learn knowledge through watching lecture videos. This method may apply to theoretical subjects, but for engineering courses--since they have strong practical background--watching videos is not an effective way for these courses. In order to solve this problem, the authors offer this new approach: that is, students learn knowledge by playing as different roles and doing and concluding different tasks themselves. And all tasks form a whole project. This project based case learning method uses "learning-by-doing" as a central theme and E-learning as a carrier. Compared with video based learning, this new method is a combination of theory and practical operation that enable the students to master the knowledge in engineering subjects more thoroughly and profoundly.