The purpose of this study is to examine the possibility of discriminant function as a large scale direct evaluation method of oral communication ability. To achieve this purpose, this study analyzed self-introduction dialogues of 111 university students. Through discriminant analysis, this study induced the discriminant function that discriminate optimally the oral communication ability of students. The canonical correlation coefficient of this discriminant function was .652, and was statistically significant(p=.002). Also the hit-ratio of this function verified as a statistically significant one. The conclusions of this study are next; First, the discriminant function that induced like this study can be a large scale direct evaluation method of oral communication ability. Second, the conventions of diverse conversation genres should be explored to induce discriminant function that have both reliability and validity. Third, studies on the nature of oral communication ability should be continued.