This research identifies the main factors of the psychological climate that directly affect the performance of banking employees in Vietnam. Besides, this research also takes into consideration the differences in gender, age, educational level, and income on working performance. A survey was obtained from 207 employees working at joint-stock commercial banks and the analysis was handled with SPSS 20 software supports. The result shows that the measurement scales meet the requirements of validity and reliability. Regression analysis demonstrates that there are four factors directly affecting the working performance: friendliness, personal development and learning opportunities, straight and open communication, and the support from the senior management. These four factors have created a healthy psychological climate in the banks, where employees will feel comfortable and happy to improve work performance. Furthermore, this research has found that the higher the income, the more efficiently employees will work. The results of this research contribute to the measurement scale of working environment factors. At the same time, this research also proposes some recommendations for organizational managers to build a reasonable working environment that can inspire a sense of mental comfort for employees to work at their full capacity and to achieve the highest performance.