The first paragraph of Article 35 of the Labor Union Law regulates that “the employer or his agent shall not refuse to employ, dismiss, or give other unfair treatments to a worker by reason of his holding office in a labor union.” in order to protect the union rights of the labor. If a worker is dismissed by the employer due to his serves in the labor union, the litigation regarding the dispute over the justice of the dismissal will be initiated before the court. At present, the Judges of the court in Taiwan tend to refuse to admit the fact that the employers discriminate the workers who hold office in labor union, and examine the fact only in accordance with Article 11 of the Labor Standards Act rather than the first paragraph of Article 35 of the Labor Union Law. Such judgments and their reasoning have been criticized seriously by the academic and shall be subject to the rectification further. Many countries have recognized the legislation based on the protection of labor’s right . For example, under the unfair labor practices of Japan, the first paragraph of Article 7 of the Japan Labor Union Act has prohibited the dismissal which is defined as the disadvantageous treatment. In reference of the application of the rule in Japan, when the claims of workers and employers are both sustained, it will result in the mixed motives and as such, the academic and the Judges in Japan have developed the theory of the predominant factor. Therefore, considering the said concerns, this Essay first examines the tendency of the court decisions in Taiwan and relevant regulations, and then researches the Japan’s administrative relief over disadvantageous treatment of union members in unfair labor practices. Finally, this Essay compares the two different legal systems and make the suggestions regarding the part of the Japan laws which can be introduced into Taiwan.