In recent years, the average salary in Taiwan has not risen up with the economic growth; therefore, cases that entrepreneurs started their own business has increased year by year. Based on cognitive theory, this study also discussed the entrepreneur behavior of opportunity recognition, and discussed the relationship between the cognitive difference between expectative opportunity and actual opportunity and the performance of entrepreneurship through the factor, such as entrepreneurial resource, prior knowledge, and entrepreneurial alertness. At last, this study gave some advice of successful opportunity recognition. This study collected 242 samples in total by using questionnaire method for the entrepreneur of SMEs in Taiwan. There are 214 valid questionnaires among all the samples. Analysis using structural equation modeling in this study reveals that the measurement model has good reliability and validity. The empirical results of structural model showed that (1) for Expected Opportunity and Actual Opportunity, Entrepreneurial Resource aspect has significantly positive effect. (2) for Expected Opportunity and Actual Opportunity, Prior Knowledge aspect has no significant impact. (3) for Expected Opportunity, Entrepreneurial Alertness aspect has significantly positive effect; however, for Actual Opportunity, Entrepreneurial Alertness aspect has no significant impact. (4) both Expected Opportunity and Actual Opportunity have a positive impact on the Performance of Entrepreneurship.