The purpose of this study was to investigate the sport participation motivation and social support of elite soccer players in Taiwan. Participants of this study were players who signed up for the 2012 National Football League (NFL) and Taiwan Ladies League (TLL) in Taiwan. A total of 278 effective questionnaires were collected, and analyzed by using descriptive statistics analysis, Independent Sample t -test, One-way ANOVA, Repeated measures ANOVA and Pearson's Product Moment Correlation with the assistance of SPSS for Windows 12.0. The main results of this study are: 1. There were four main factors of the players' participation motivation. The order of importance from highest to lowest was: mastery orientation, competition orientation, victory orientation, and challenge orientation. 2. There were five main factors of the players' social support. The order of importance from highest to lowest was: teammate support, coach support, family support, employer support, and supporter support. 3. Comparing the participation motivation in different variables, there were significant differences in all demographic variables apart from "practicing days" and "practicing hours". 4. Comparing the social support in different variables, there were significant differences in all demographic variables apart from "age", "experiences of play" and "best game performance". 5. There was significantly correlation between the players' participation motivation and social support.