The passage of the International Convention on the Elimination of All Forms of Racial Discrimination in 1965 did not help Hong Kong to protect its citizens from discrimination at all, although Hong Kong has been a member of the convention since 1969. The H.K government had done nothing to deal with its racial discrimination problem for decades, either under Britain’s rule or China’s rule. However, some 40 years later in 2006, the H.K. government submitted a bill proposal to the Legislative Council which aimed to eliminate racial discrimination. This caused us to inquire why the H.K. government changed its mind to deal with the problem of racial discrimination. In this paper, we attempt to figure out the explanation by interviewing H.K. legislators, government officials and staff from NGOs, and analyzing discussions and debates during the legislative process.The results indicate that the enactment and the passage of the Race Discrimination Ordinance in Hong Kong can be explained by the boomerang model of the transnational advocacy network which creates tremendous pressure on the Hong Kong Government to take action. On the one hand, NGOs in Hong Kong that advocate the elimination of racial discrimination played an active role in lobbying legislators and pressuring the H.K. Government to enact a bill that can decrease the extent of racial discrimination in Hong Kong. On the other hand, these NGOs also established a strong connection with actors outside Hong Kong such as international organizations and the United Nations’ Committees to force the H.K. government to pay attention to this issue and further to change their behavior. In short, the development of a transnational advocacy network among Hong Kong NGOs and the international regimes and international civil society has accelerated the enhancement of the Race Discrimination Ordinance and changed the policy of anti-racial discrimination of the Hong Kong Government.