The main purpose of this study was to explore the elementary school teachers' cognition and attitude of online games. The research method was investigation into subjects' understanding and feeling about online games and the used instrument was a questionnaire. The subjects of this study were the Tainan elementary school teachers. The methods of data analysis were t-test, ANOVA, Pearson product-moment correlation and so on. The findings of this study were listed as followed: 1. The online games' cognition and attitude of male teachers worked in Tainan elementary schools were significantly higher than that the female teachers of Tainan elementary schools had. 2. The online games' cognition and attitude of Tainan elementary teachers who were less than 30 years old were significant better than that the teachers who were more than 30 years old had. 3. The online games' cognition and attitude of Tainan elementary school teachers who have played online games were significantly higher than that the teachers who haven't played online games had. 4. Tainan elementary school teachers who had online experiences at home had better attitude toward online games than those who hadn't online experiences at home. 5. There was significant positive correlation between Tainan elementary school teachers' cognition of online games and their attitude toward online games.