National Science Day is a big popular science event in China with significant impacts and recent years have borne witness to rapid development in its online new media application. The research summarizes the current development of official micro-blog and WeChat public account of National Science Day, analyzes their impacts as well as the impacting factors, learns experience from the official micro-blog and WeChat public account of other related activities in China and finally puts forward some suggestions. The analysis indicates that there exists a certain gap between content features and service function of official micro-blog and WeChat public account of National Science Day and other related activities. Official micro-blog and official WeChat public account play an active role in communication and promotion of this activity. The paper suggests that efforts should be made to make big popular science activities in China develop in a better manner by learning good experience and advantages of other activities.