Abstract: With the rapid development of network technology, social network has become part of people's lives, and informal learning has also attracted more and more attention, while study found that 70 percent of people got their knowledge from the informal situation. As the most widely used and influential platform, social network is the biggest virtual situation for people's informal learning. However, due to the fragmentation of acquired knowledge, it requires us to effectively integrate the scattered knowledge within a systematic framework by applying knowledge management, and then realize innovative knowledge. Through the study on the features, relationships and impact factors of social network, informal learning and personal knowledge management, this paper proposed the appropriate strategies to improve the learning efficiency.

Key words: Social network