Objective To understand the experience， knowledge and attitudes of e-cigarette users in Shanghai， and to provide evidence for the development of intervention programs for e-cigarette use.

Methods The Respondent-Driven Sampling （RDS） method was used to recruit 40 e-cigarette users for qualitative interviews from November 2020 to February 2021. NVivo （11.0） software was used to code interview records， and the thematic pattern and relationship analysis were conducted.

Results In terms of the reasons and user experience of e-cigarette use， most respondents used e-cigarettes for the first time after recommendation of friends； The reasons for the current use of e-cigarettes focus on the subjective feelings generated by the use of e-cigarettes （easy to use， replacing traditional tobacco， and having many flavors）. Compared with traditional tobacco use， respondents said e-cigarettes tasted good and had no physical impact （they could be used all the time without making them uncomfortable）. In terms of the awareness of e-cigarette use related knowledge， the respondents' opinions on whether e-cigarettes caused health risks were mostly based on their own experience of using them， and they said it was difficult to identify real information online. As for whether they were interested in relevant knowledge， most respondents said they wanted to learn about the professional knowledge related to e-cigarettes. Regarding the attitude related to the use of e-cigarettes， most respondents believed that e-cigarettes are addictive， e-cigarettes are not a safe alternative to traditional tobacco， and e-cigarettes couldn't help them quit smoking. Three out of ten respondents said they supported including e-cigarettes in the Regulation on Smoking Control in Public.

Conclusion There are certain characteristics of e-cigarette users' feelings， related knowledge and attitude towards e-cigarette use that should be targeted to carry out publicity， education and intervention.