The main purpose of this study was to understand relationships among the personality and college Baseball player's stress on learning. The researcher of this study applied questionnaires survey, and referring to the documents relating to student's personality and stress in schools and the chart of self-made "Questionnaires On personality and stress on learning" as the resources of information, The research objects were 262 Baseball player's in Taiwan. The data was analyzed through the methods of Pearson's product moment correlation, Stepwise regression. The results of the research are five factors of personality were Factor of agreeableness, emotional stability, conscientiousness, openness to experience and emotional experience. Learning stress has two aspects. First academic stress was three factors of tendency of academic, examination and Colleagues' Pressure. Second sport stress was three factors of tendency of competition, training and health. Other result, The study reveals positive correlation between personality and college Baseball player's learn stress, among middle correlation with openness to experience and emotional experience. The results of this research state that different personality of baseball player in primary unit does influence their learn stress. It was suggested for the researchers in the future. Help to player develop the second kind of professional skills and to make an overall examination for the national senior high player. And comparison should be made between this study and others.