This study treated one of the top three securities firms, S, in Taiwan as the subject, and conducted cross-sectional analysis on all dealers¡¦ personal information and performance. By exploring the dealers¡¦ personality traits, this study probed into the effect on the dealers¡¦ job performance, and attempted to find the key success factors of their job performance from the traits of the dealers¡¦ physical dimension, experience or numerological characters. Finally, this study attempted to recognize the dealers¡¦ key success factors. The findings can serve as references for securities firms¡¦ employment and management of the dealers, in order to contribute to the personnel affair management in security industry. Unlike past studies that use questionnaire survey as the research method, this study massively analyzed the internal data of the company. The research was conducted in 2010, and collected 1175 samples of the dealers in the securities firm S. The variables of the dealers¡¦ job performance are the dealers¡¦ yearly market share of spot share, purchase amount of spot share, and net fee income. Regarding the dealers¡¦ personality traits, there are three dimensions (physical dimension, experience and numerological characters), including five variables. Empirical analysis is conducted by basic descriptive statistics and analysis of variance. The main findings are summarized as follows: 1) There is a significant relationship between the dealers¡¦ job performance and ages, and it reveals a significant difference. Female dealers¡¦ job performance is significantly superior to male dealers, indicating that physical dimension will influence job performance. 2) There is a positive relationship between the dealer¡¦ working years and job performance, indicating that experience will influence job performance. 3) There is a significant relationship between the dealers¡¦ job performance and star signs, and it reveals a significant difference. Sagittarius is advantageous for the dealers¡¦ business, indicating that numerological characters will influence job performance. This study concludes that the interaction between the dealers¡¦ gender and working years (star signs) significantly influences the job performance. Keywords: Securities dealer; personality traits; job performance; analysis of variance