With the rise of the concept of "Internet + education", the continuous popularization of Internet technology has brought new challenges to the traditional teaching methods of colleges and universities, and the growing diversified and personalized learning needs of students. Online college student education is the development of the current education model. This paper is going to explore online education in 21st century. Online education originated in the United States, but after years of development and exploration, today, China has been fully promoted and developed under the impetus of Internet thinking and mobile technology. This article will analyze the development history of online education, the growth mode of MOOC and its advantages and disadvantages, discuss the strategies for students to participate in online courses, this paper explores the future of online education and provides some advice to students and teachers.