The purpose of this study is to explore English speaking characteristics of Korean university students as indicators of language ‘Complexity’, ‘Accuracy’ and ‘Fluency’, and to analyze the correlation among the factors to improve English speaking skills of Korean university students. In total, 50 university students participated in the study and carried out the speaking test. The result from t-test revealed that the distinction between the upper and lower English speaking groups, as determined by the overall averages of Complexity, Accuracy, and Fluency, was significant. A Pearson analysis showed that ‘Complexity’ had a moderate correlation with both ‘Accuracy’ (.446) and ‘Fluency’ (.430), while ‘Accuracy’ and ‘Fluency’ has low correlation (.398). There were also statistical differences between the upper and lower groups in the degree of influence of each factor, ‘Complexity’, ‘Accuracy’, ‘Fluency’. Based on ‘Complexity’, ‘Complexity’ was highly correlated (.734) and relatively highly correlated (.506) with ‘Accuracy’ in the upper and lower groups, respectively. Based on ‘Accuracy’, only ‘Accuracy’ and ‘Complexity’ has a moderate correlation in a lower group whereas there is no correlation in ‘Accuracy’, ‘Complexity’, and ‘Fluency’ in the upper group. In the case of ‘Fluency’, there was no correlation with ‘Complexity’, ‘Accuracy’ in either group.