Purpose: Given the current lack of literature in the background of China labor force, this study aims to investigate the relationships among job satisfaction, perceived union instrumentality, and unionization from a reference-frame-based perspective and explore the referred relationships in the context of Chinese labor market. Design/methodology/approach: The study introduces perceived union instrumentality as a mediator to the relationship between job satisfaction and unionization. The applicability of western theories was tested in the Chinese context by a questionnaire survey on 390 employees who were working in private sectors of Jiangsu Province in China. Four hypothesis were proposed and tested by data analysis to verify the model. Findings: The study found that most aspects of job satisfaction were negatively correlated with unionization and perceived union instrumentality, while perceived union instrumentality had a positive relationship with unionization. Perceived union instrumentality was also found to have a mediating effect on the relationship between job satisfaction and unionization. Originality/value: The paper adapted and tested a number of western industrial relation theories in the backdrop of China, contributing to the gap in Chinese-context research by examining the relationships between job satisfaction, unionization and union instrumentality of Chinese employees. It pays a regular contribution to labor union studies both inside and outside China.