This study is to explore the different perception of workplace happiness of employees during and after the process of mergers and acquisitions between two high-tech companies. We hope to understand the impact of organizational culture on workplace happiness of employees in the case of merger between these two Companies . This study uses qualitative research methods to investigate the effect of mergers and acquisitions on the happiness of employees in the workplace. We find that “ wages and benefits “ is the primary factor of the happiness of employees at work. The secondary one is the factor of ”working stability” and “social perception “ is the most minor. Consequently, the employees experienced the difference of corporate cultures after being acquired, and the workplace happiness was significantly affected.