The user experience of mobile phone products has been widely concerned, AQ1 while the fluency of mobile phone will also affect the user experience. However, the factors that affect the fluency of mobile phone have not been fully discussed. Present study used semi-structured focus group interviews with 25 participants to explore the definition of smartphone fluency and the influencing factors of smartphone fluency. The interview results showed that among the 13 factors which affect mobile phone purchase, fluency is the most important factor. Fluency refers to the degree of ease with which an individual is able to perform some tasks. It usually means a high level of experience or practice. By coding and analyzing the user’s evaluation, this study summarized six factors that affect smartphone fluency experience, including connection (visual sense when frames or tasks switch), response delay (the time interval between a user completing an operation and the smart phone providing a recognizable response), nonoperational system failure (the misoperation during mobile phone operation which are not related to lack of knowledge), visual experience (sharpness, distinguishability, color matching), operation error rate (error rate when users operate a mobile phone), simplicity (the minimum number of operation steps required to complete a task). This study defines the fluency of mobile phones and identifies the dimensions of smart phone fluency, which can provide research basis for improving fluency experience, and provide new research ideas for future direction of user experience improvement.