Since 2003, the Taichung Jazz Festival has become one of the major annual events regularly held in Taichung City.The number of tourists and the tourism business opportunities brought by this festival has been increasing year by year, even reaching more than 1 million participating tourists/times ever since 2015. In terms of traditional assessment methods for great events, we used to obtain analytic information such as visitor satisfaction or the number of people through questionnaires. However, different levels of issues concerned by tourists cannot be easily understood through standardized questionnaires. Due to the popularization of online platforms and smart phones, people tend to voluntarily provide some information when they are participating in an activity. Such coordinated information is namely "Volunteered geographic information" (VGI), ex. "check-in" created by anyone. People can show their positive and negative messages by expressing their words about certain places (food, landscape, etc.), which can can make up for the shortcomings of traditional questionnaires. In this study, through the API provided by Facebook and by writing a web crawler program, we downloaded a total of 46,260 comments/messages written by people during the period of the Jazz Festival. Then, by means of Chinese word segmentation and through keywords, statistical analyses were conducted on two indicators shown by these tourists regarding the Jazz Festival: 1. Satisfaction about this event: To analyze people's positive and negative evaluations of the handling of this event, as well as their feelings; 2. Suggestions for event improvements: To analyze all aspects of concrete problems and suggestions for improvements proposed by people for this event. In this study, through collecting VGI data and constructing unstructured information analysis methods, explorations were made, concerning people's intuitive feeling about Jazz Festival from a mass perspective. In addition, comparisons and analyses against traditional questionnaires were conducted. Therefore, the findings of this study can serve as a reference for future leisure activity surveys combined with VGI data analyses.