Abstract: Since the 18th National Congress of the Communist Party of China, Chinese government hasmade many historical breakthroughs in anti-corruption. However, fighting corruption to the end still needs steady support from scientific anti-corruption institutions and systems. The Independent Commission Against Corruption (ICAC) of Hong Kong is an example whose experiencecan be used for reference for anti-corruption agenciesin Mainland China. The paper first clarifies problems of anti-corruption institutions in Mainland China and then indicates future reformationdirection by a comparative study between Hong Kong and Mainland China. The paper also puts forward four features that anti-corruption agencies should have,i.e. independence, authoritativeness, integrity and specialty. These features are also the analytical framework of the whole study. Holding the four-big features is the ultimate goal of the reformation of anti-corruption agenciesin Mainland China. There are three reformation tasks for them, i.e. integration reformation, professionalization reformation and organization structure reformation.