Factors Influencing Members¡¦ Commitment and Participation in the Union Abstract Due to the special situation of Taiwan economical and political development in the past, unions were unable to provide their member the function they ought to do. However Government declared martial law ended in 1989, it offered Taiwan unions a new opportunity to perform their function. Recently Human Resource Management School suggests that company never need union if they have offered work conditions satisfied by their employees. So far, neither union operation nor human resource management can coordinate Labors-Employer relation completely. Thus, it is hard to decide which way is suitable for Taiwan¡¦s situation. Therefore, the extent of Taiwan labor¡¦s commitment and participation in the union is crucial in deciding the way of coordinating Labor-employer Relation. First, this study selected some of demographics in order to realize if there are differences among members with different demographics. Second, the study also selected some factors, including Recognizing and Evaluating of Union, Job Satisfaction, Organizational Commitment and Union Instrumentality to realize if there are any effects among the factors of Union Commitment and Participation. The critical findings of this research are as follows: 1. There are significant differences among gender, age, married status, company run by state or local people, work tenure, union tenure and some factors of union commitment and participation dimension. But there are no significant between education and union commitment and participation dimension. 2. Some factors of recognizing and evaluating of union, job satisfaction, organizational commitment have relation in some factors of union commitment and participation dimension. Some factors of recognizing and evaluating of union, job satisfaction, organizational commitment have significant effects in some factors of union commitment and participation dimension. 3. Union instrumentality has significant positive relation and effects in union commitment and participation. Keyword: union commitment, union participation, union instrumentality, job satisfaction, organizational commitment.