The Republic of China¡¦s Legislative Yuan approved International Covenant on Civil and Political Rights and International Covenant on Economic, Social and Cultural Rights, and the Enforcement Act of the two international human right covenants on March 31 th , 2009. The President promulgated the Enforcement Act of the two international human right covenants on April 22 th , 2009, and ratified the two international human right covenants on May 14th, 2009. Subsequently, the President ordered the Executive branch to promptly formulate a complete set of relevant legislative framework to domesticate the two international human right covenants. Such move symbolizes that the government has taken a significant step forward on the human right issues. Presently, the government should comprehensively review all the laws, regulations, administrative ordinances, and administrative measures for the protection and deepening of human rights especially after the ratification of the two international human right covenants. Under the contemporary trend of embracing human rights, democratic states have incorporated alien into their national fundamental rights protection system. Within the scope of protection, aliens enjoy the same fundamental human rights as that of the country¡¦s nationals, and are equally protected under the constitution. However, aliens are different from nationals in certain regards. Therefore, on the issues of the suffrage, social welfare, and economic human rights, discrimination toward aliens are permissible under the two international human right covenants and the constitutions of each state. However, according to constitutional equal protection theory, discrimination on aliens could not be premised on prejudice, unless there is a legitimate purpose and reasonably distinguishable criteria. Under international human rights development in the 20th century, international norms likewise influence the rights enjoyed by aliens and the treatments to alien in a state, in addition to limits stipulated by constitution and the laws of the state. The research purpose of this thesis is to discuss if the rights enjoyed by aliens and the treatment of aliens in our state conform with the two international human right covenants and consistent with the equal protection principle under the ROC constitution. In addition to the category of alien, there is a distinct set of laws and regulations that apply to people from the Mainland, Hong Kong, and Macau in Republic of China (Taiwan). To appreciate a macro picture, the scope of the article will include aliens, people from the Mainland, Hong Kong, and Macau, and identify the legal status of each category of people in Republic of China (Taiwan). Based on the aforementioned research purpose, the thesis will firstly introduce the contents of the two international human right covenants and the constitutions of each state in order to understand the fundamental human rights that aliens enjoy. The thesis will also illustrate the discriminations permitted by the constitution of each state and the two international human right covenants, and refer to the legislative and judicial practice of each state, to analyze and identify reasonable discrimination criteria and judicial review standards for aliens in each state. Based upon the above criteria, the article will proceed to survey and discuss the relevant applicable regulations to aliens, people from the Mainland, Hong Kong, and Macau in Republic of China (Taiwan), and also review the multi-track legislative model. I will explore the existing norms and describe their inconsistencies with the two international human right covenants or their violations of the equal protection principle under the Constitution, and make recommendations for the legislators to amend the relevant legislations accordingly.