The political development in Hong Kong after 1997 displays certain similarities to that in Taiwan. This article uses the term "Taiwanisation of Hong Kong politics" to generalise this trend. A closer look at Hong Kong and Taiwan politics reveals that the essence of this "convergence" is the emergence of "exogenic infighting" that comprises two dimensions, political antagonism and ethno-nationalism. Indeed, "exogenic infighting" politics could be explicated largely by China's triadic leverage. By "localising" this leverage, the centrifugal forces in Hong Kong's constitutional design of autonomy activate two mechanisms, namely intensifying polarisation and mutual shaping, which eventually shape the political trajectories of Hong Kong.