With the rapid development of wearable electronic technology, flexible strain sensors have received extensive attention in the field of electronic skin and robots due to their high transduction factors. However, how to reduce the manufacture cost is a huge challenge. In recent years, the rapid development of printed electronic technology has promoted the development of flexible strain sensor, which has been applied in some new fields, such as intelligent packaging. According to the research progress in our group, the mechanisms, manufacturing methods and applications of fully-printed flexible strain sensor were summarized. A large number of studies have shown that flexible strain sensors have been applied to intelligent packaging. The use of printed electronic technology to manufacture smart packaging is beneficial to reduce its manufacturing costs and promote its practical application.