Employee job satisfaction is an evaluation of satisfaction with various aspects such as the content, characteristics, environment, effort, and rewards of their work. It reflects employees' attitudes and emotions and significantly impacts customer and shareholder satisfaction of a corporation. Grassroots employees, situated on the front lines of corporate production and operations, not only play an indispensable foundational role in daily operations but also enact corporate strategic deployments. However, the management of their satisfaction receives significant attention. Traditional views consider compensation the most crucial factor, yet in knowledge-intensive enterprises, the needs of grassroots employees are more complex and their satisfaction is influenced by more than just salary. As a typical knowledge-intensive small and medium-sized private enterprise, R Project Management Company also faces certain safety risks concerning the satisfaction of its grassroots employees. Based on a survey, this study finds that job nature, job rewards, company interpersonal relationships, and management positively influence employee satisfaction, while the impact of company culture is relatively weak. The study also found that the age, education, length of service, and position of grassroots employees affect their satisfaction. Finally, based on the specific circumstances of R Project Management Company, the study proposes five suggestions to help the company improve management, enhance job rewards, optimize interpersonal relationships, improve the nature of the work, and adopt appropriate measures for different grassroots employees to increase their satisfaction and sense of identification.